Suspension device control mechanism and suspension device control method

Abstract

Provided are a suspension device control mechanism and a suspension device control method capable of improving the feel of steering. A roll control unit of a suspension control device determines, by a high select unit and a control intervention threshold unit, whether a plurality of steering angle command values (target lateral jerk and SBW steering angle estimated lateral jerk) exceed a threshold (dead zone). The target lateral jerk is a steering angle command value based on a normative steering angle (target steering amount) corresponding to a normative turning state of a vehicle 1. The SBW steering angle estimated lateral jerk is a steering angle command value based on an input steering angle (SBW steering angle) input to a steering wheel which is a steering member of the vehicle 1. The roll control unit controls the suspension by referring to the steering angle command value (the target lateral jerk or the SBW steering angle estimated lateral jerk) that exceeds the threshold.

Description

Suspension control mechanism and suspension control method

[0001] The present invention relates to a suspension control mechanism and a suspension control method mounted on a vehicle such as an automobile.

[0002] For example, Patent Document 1 describes a suspension control device that performs anti-roll control (roll control that suppresses roll) using a threshold value (j1) that corresponds to lateral jerk caused by turning of the vehicle.

[0003] JP 2016-101868 A

[0004] The technology described in Patent Document 1 is based on a vehicle equipped with a general steering device (a steering device in which the wheels and the steering wheel are mechanically connected). This may result in, for example, in insufficient suspension control to suppress the roll of the vehicle body, which may increase the roll rate. This may result in a deterioration in steering feel.

[0005] An object of the present invention is to provide a suspension control mechanism and a suspension control method that can improve steering feel.

[0006] The present invention is preferably a suspension control mechanism for controlling a suspension of a vehicle, the suspension control mechanism comprising a speed acquisition unit for acquiring a vehicle speed of the vehicle, a steering angle command value acquisition unit for acquiring a steering angle command value corresponding to a steering angle of the vehicle, the standard steering angle command value acquisition unit acquiring a standard steering angle command value which is a command value based on the vehicle speed and a standard steering angle which is a steering angle corresponding to a standard turning state of the vehicle, an input steering angle command value acquisition unit acquiring an input steering angle command value which is a command value based on the vehicle speed and an input steering angle which is a steering angle input to a steering member of the vehicle, and a steering angle command value acquisition unit that acquires a plurality of steering angle command values ​​from a group including at least two of the above; a judgment unit that judges whether the acquired plurality of steering angle command values ​​have exceeded corresponding threshold values, and a command value determination unit that controls the suspension device by referring to the value when the judgment unit judges that only one steering angle command value has exceeded the threshold value, and that controls the suspension by referring to the largest steering angle command value when the judgment unit judges that two or more command values ​​have exceeded the threshold value.

[0007] The present invention also preferably relates to a suspension control method for controlling a suspension of a vehicle having a steer-by-wire by supplying a current or a voltage, the suspension control method including: an input steering angle acquisition step for acquiring an input steering angle input to a steering member of the vehicle; a vehicle speed acquisition step for acquiring a vehicle speed of the vehicle; and a power supply step that is executed after the input steering angle acquisition step and the vehicle speed acquisition step and supplies the current or the voltage, the power supply step starting to supply the current or the voltage when a result of multiplying the input steering angle and the vehicle speed is equal to or greater than a predetermined value.

[0008] According to one embodiment of the present invention, the steering feel can be improved.

[0009] 1 is a schematic diagram showing a vehicle equipped with a suspension control device (suspension control mechanism) according to a first embodiment. FIG. 1 is a block diagram showing the suspension control device in FIG. 1. FIG. 2 is a block diagram corresponding to the processing until a roll control command in FIG. 2 is output. FIG. 3 is a block diagram showing the target steering amount calculation unit in FIG. 3. FIG. 4 is a block diagram showing the target lateral jerk calculation unit in FIG. 3. FIG. 4 is a block diagram showing the SBW steering angle estimated lateral jerk calculation unit in FIG. 3. FIG. 5 is a block diagram showing the roll control unit in FIG. 3. FIG. 6 is an explanatory diagram showing an example of driving assist control of a vehicle equipped with a steer-by-wire steering device. FIG. 7 is a block diagram showing the processing until a roll control command is output according to a first modified example. FIG. 8 is a block diagram showing the planned lateral jerk calculation unit in FIG. 9. FIG. 9 is a block diagram showing the roll control unit in FIG. 10. FIG. 11 is a block diagram showing the processing until a roll control command is output according to a second modified example. FIG. 12 is a block diagram showing the roll control unit in FIG. 13. FIG. 14 is a block diagram showing the processing until a final control command in FIG. 14 is output. FIG. 15 is a block diagram showing the actual steering angle estimated lateral jerk calculation unit in FIG. 16. FIG. 17 is a block diagram showing the road surface input consideration sprung vibration damping control unit in FIG. 15. FIG. 18 is a block diagram showing the roll control unit in FIG. 15. 21 is a characteristic diagram showing time variations in lateral acceleration, lateral jerk (lateral jerk), damper control command, and roll rate for a second embodiment (present example) and a comparative example (conventional example). FIG. 22 is a block diagram corresponding to the processing until a final control command is output according to a third modified example. FIG. 23 is a block diagram showing the roll control unit in FIG. 20. FIG. 24 is a block diagram corresponding to the processing until a final control command is output according to a fourth modified example. FIG. 25 is a block diagram showing the roll control unit in FIG. 24. FIG. 26 is a block diagram corresponding to the processing until a roll control command is output according to a fifth modified example. FIG. 27 is a block diagram showing the steering system determination unit in FIG. 24.

[0010] Hereinafter, a suspension control mechanism and a suspension control method according to an embodiment and a modification thereof will be described with reference to the accompanying drawings, taking as an example a case where the mechanism and the method are applied to a four-wheeled vehicle.

[0011] 1 to 8 show a first embodiment. In Fig. 1, a vehicle body 2 constituting the body of a vehicle 1, which is an automobile, is provided on the underside of a vehicle body 2, which comprises, for example, left and right front wheels 3, 3 and left and right rear wheels 4, 4, a total of four wheels 3, 4. Each wheel 3, 4 is composed of a tire and a wheel. Suspensions 5, 7, which are suspension devices, are provided between the vehicle body 2 and the wheels 3, 4.

[0012] That is, front-wheel suspensions 5, 5 (hereinafter referred to as front-wheel suspensions 5) are provided between the left and right front wheels 3, 3 and the vehicle body 2. The front-wheel suspensions 5 include, for example, suspension springs (not shown) and adjustable damping shock absorbers 6 (hereinafter referred to as shock absorbers 6) provided in parallel with the springs. Rear-wheel suspensions 7, 7 (hereinafter referred to as rear-wheel suspensions 7) are provided between the left and right rear wheels 4, 4 and the vehicle body 2. The rear-wheel suspensions 7 include, for example, suspension springs (not shown) and adjustable damping shock absorbers 8 (hereinafter referred to as shock absorbers 8) provided in parallel with the springs.

[0013] The shock absorbers 6 and 8 are configured by semi-active dampers, which are hydraulic cylinder devices (variable damping shock absorbers) that can adjust the damping force. That is, the vehicle 1 is equipped with a semi-active suspension system that uses variable damping shock absorbers. The shock absorbers 6 and 8 are provided between the body 2 and the wheels 3 and 4 of the vehicle 1. The shock absorbers 6 and 8 are actuator devices (force generating mechanisms) that vary the force that suppresses relative displacement between the body 2 and the wheels 3 and 4. Specifically, the shock absorbers 6 and 8 are variable damping force generating devices (variable damping shock absorbers).

[0014] The characteristics of the damping force generated by the shock absorbers 6, 8 (damping force characteristics) are variably controlled by a suspension control device 21, which will be described later. For example, the shock absorbers 6, 8 are provided with a damping force adjusting device (not shown) including a damping force adjusting valve, a solenoid, etc., in order to adjust the damping force characteristics continuously (or in multiple stages) from hard characteristics to soft characteristics. The damping force characteristics of the shock absorbers 6, 8 are variably adjusted in accordance with a damper command current (command current, control current) supplied from the suspension control device 21 to the damping force adjusting device.

[0015] The damping force adjustment valve may have a conventionally known structure, such as a pressure control system that controls the pilot pressure of a damping force generating valve or a flow control system that controls the passage area. The shock absorbers 6 and 8 may be actuator devices (force generating mechanisms) such as pneumatic dampers, electromagnetic dampers, electrorheological fluid dampers (ER dampers), and magnetic fluid dampers, as long as they can adjust the damping force continuously (or in multiple stages). The shock absorbers 6 and 8 may also be actuator devices (force generating mechanisms) such as air dampers (air suspensions) that use air springs, hydraulic dampers in which front, rear, left, and right hydraulic cylinders are connected by piping, and stabilizers that apply force to the movement of the left and right wheels.

[0016] Furthermore, the shock absorbers 6, 8 may be actuator devices (force generating mechanisms) capable of generating thrust, i.e., full-active dampers configured with hydraulic actuators, electric actuators, or pneumatic actuators. In other words, the vehicle 1 may be equipped with a full-active suspension system using full-active dampers. That is, the shock absorbers 6, 8 are actuator devices (force generating mechanisms) capable of adjusting the force generated between the body 2 side and the wheels 3, 4 side of the vehicle 1, and various actuator devices (force generating mechanisms) can be used, such as variable damping hydraulic dampers, electrorheological fluid dampers, pneumatic dampers, electromagnetic dampers, hydraulic actuators, electric actuators, and pneumatic (air) actuators.

[0017] The vehicle 1 is provided with a vehicle behavior detection means (not shown) for detecting the behavior of the vehicle 1. The vehicle behavior detection means corresponds to at least one of a longitudinal acceleration sensor, a lateral acceleration sensor, a wheel speed sensor, a yaw rate sensor, a vehicle speed sensor, a vehicle height sensor, a sprung vertical acceleration sensor, a sprung vertical velocity sensor, an unsprung vertical acceleration sensor, and an unsprung vertical velocity sensor. The vehicle behavior detection means (vehicle behavior detection sensor) detects the behavior of the vehicle (for example, at least one of a longitudinal acceleration, a lateral acceleration, a wheel speed, a yaw rate, a vehicle speed, a vehicle height, a sprung vertical acceleration, a sprung vertical velocity, an unsprung vertical acceleration, and an unsprung vertical velocity). The vehicle behavior detection means (vehicle behavior detection sensor) outputs a signal corresponding to the detected vehicle behavior to the suspension control device 21.

[0018] In the first embodiment, the vehicle 1 includes, as vehicle behavior detection means (vehicle behavior detection sensors), for example, a vehicle speed sensor (not shown), five vertical acceleration sensors (not shown), and a steering angle sensor 12 as an input steering angle sensor. The vehicle speed sensor detects the vehicle speed. Detection information from the vehicle speed sensor (a signal corresponding to the vehicle speed) is output to a suspension control device 21 via a communication line 9 such as a CAN (Controller Area Network). The five vertical acceleration sensors correspond to, for example, three sprung acceleration sensors and two unsprung acceleration sensors.

[0019] The three sprung acceleration sensors are provided on the vehicle body 2, which is the sprung side of the vehicle 1. For example, the three sprung acceleration sensors are provided at a position corresponding to the left front wheel 3, a position corresponding to the right front wheel 3, and a position corresponding to one of the left and right rear wheels 4 (for example, the right rear wheel 4). The three sprung acceleration sensors detect the acceleration of the vehicle 1 (vehicle body 2) in the vertical direction at their respective positions. Detection information (signals corresponding to the vertical acceleration) from the three sprung acceleration sensors is output to the suspension control device 21 via a communication line 9 such as a CAN. The vertical acceleration on the left rear side of the vehicle body 2 (the position corresponding to the left rear wheel 4) can be estimated by the suspension control device 21, for example, using the vertical accelerations of the three sprung acceleration sensors.

[0020] The two unsprung acceleration sensors are provided on the wheel 3 side, which is the unsprung side of the vehicle 1. For example, two unsprung acceleration sensors are provided on the left front wheel 3 side and the right front wheel 3 side, respectively. The unsprung acceleration sensors detect the vertical acceleration of the front wheels 3, 3, which are the unsprung side, at their respective positions. Detection information (signals corresponding to vertical acceleration) from the two unsprung acceleration sensors is output to the suspension control device 21 via a communication line 9 such as a CAN. The vertical acceleration of the unsprung part on the left rear wheel 4 side and the vertical acceleration of the unsprung part on the right rear wheel 4 side can be estimated by the suspension control device 21, for example, using the vertical accelerations of the unsprung part acceleration sensors on the two front wheels 3, 3 side and a travel distance (delay distance) calculated from the vehicle speed.

[0021] The steering angle sensor 12 detects a steering angle (input steering angle) corresponding to the rotation angle of the steering wheel 11. The detection information (signal corresponding to the steering angle) of the steering angle sensor 12 is output to a suspension control device 21, for example, via a steer-by-wire control device 17 (described later) and a communication line 9 such as a CAN. In this way, the detection values ​​(detection signals, detection data) detected by the vehicle speed sensor, the five vertical acceleration sensors, and the steering angle sensor 12 are input to the suspension control device 21. In this case, as shown in FIG. 2 (described later), the vehicle speed, the five accelerations, the steering angle (SBW steering angle), etc. are input to the suspension control device 21 via the communication line 9 such as a CAN.

[0022] In the first embodiment, five acceleration sensors are provided as the vehicle behavior detection means (vehicle behavior detection sensors). However, the vehicle behavior detection means is not limited to acceleration sensors, and may include, for example, a vehicle height sensor, a stroke sensor, a displacement sensor, a preview sensor, etc. The vehicle height sensor corresponds to, for example, a sensor that detects the displacement amount of a suspension arm corresponding to the vehicle height. The stroke sensor and the displacement sensor correspond to, for example, sensors that detect the stroke amount (extension amount, contraction amount) of the shock absorbers 6, 8. The preview sensor corresponds to, for example, an external environment recognition sensor that recognizes the situation around the vehicle 1 (for example, the road surface situation).

[0023] As shown in FIG. 1 , the suspension control device 21 is connected to the shock absorbers 6 and 8, more specifically, to the damping force adjusting devices (e.g., solenoids) of the shock absorbers 6 and 8. The suspension control device 21 controls the shock absorbers 6 and 8. The suspension control device 21 is connected to the above-mentioned vehicle behavior detection sensors and / or another control device (e.g., the steer-by-wire control device 17 described below) via a communication line 9 such as a CAN (Computer Aperture Network), which is an in-vehicle LAN communication system. The communication line 9 is also called an information transmission line or a vehicle data bus. The suspension control device 21 controls the shock absorbers 6 and 8 based on vehicle behavior (e.g., vehicle speed, five accelerations, steering angle, etc.) input via the communication line 9. Note that the vehicle behavior detection sensors may be directly connected to the suspension control device 21 without going through the communication line 9 such as a CAN or another control device.

[0024] The suspension control device 21 is a control device (controller) including, for example, a microcomputer, a power supply circuit, and a drive circuit, and is also called an ECU (Electronic Control Unit). The suspension control device 21 is a controller for the suspension system, i.e., a suspension ECU (shock absorber ECU). The output side of the suspension control device 21 is connected to the damping force adjusting devices (e.g., solenoids) of the shock absorbers 6 and 8.

[0025] The suspension control device 21 controls (adjusts the damping force of) the shock absorbers 6, 8 based on various vehicle behavior information (vehicle behavior signals) including detection values ​​from vehicle behavior detection means (vehicle behavior detection sensors), commands related to automatic vehicle control (control commands, operation commands, command signals), etc. For this purpose, the memory (storage unit) of the suspension control device 21 stores a processing program for calculating the damping force to be generated in the shock absorbers 6, 8 based on the vehicle behavior information (vehicle behavior signals), a processing program for outputting a control signal (control current) corresponding to the damping force to be generated, and the like.

[0026] As shown in Fig. 2, the suspension control device 21 includes a state estimator 22 and a suspension controller 23. The state estimator 22 receives various types of vehicle behavior information (vehicle behavior signals) including detection values ​​from vehicle behavior detection means (vehicle behavior detection sensors) and commands related to automatic vehicle control (control commands, operation commands, command signals) via communication line 9. The state estimator 22 estimates the vehicle state based on the vehicle behavior information (vehicle behavior signals). The state estimator 22 outputs the vehicle behavior information input to the state estimator 22 and / or vehicle state estimation information estimated by the state estimator 22 to the suspension controller 23 as vehicle state information.

[0027] The suspension control unit 23 outputs a control signal (control current) corresponding to the damping force to be generated to the damping force adjusting devices (e.g., solenoids) of the shock absorbers 6, 8 based on vehicle state information (vehicle behavior information and / or vehicle state estimation information). The suspension control unit 23 includes a driving stability control unit 24 and a command current value calculation unit 25. The driving stability control unit 24 receives vehicle state information from the state estimation unit 22. The driving stability control unit 24 outputs a control command (driving stability control command) for improving the driving stability (postural stability) of the vehicle 1 based on the vehicle state information. The driving stability control unit 24 corresponds to, for example, a roll control unit (roll control unit 34 described below) also called an anti-roll control unit for suppressing the roll behavior of the vehicle 1. The driving stability control unit 24 (roll control unit 34) outputs a roll control command (anti-roll control command) for suppressing the roll behavior of the vehicle 1 to the command current value calculation unit 25 based on the vehicle state information.

[0028] The command current value calculation unit 25 calculates a command current (damper command current) corresponding to a command signal (control signal) for the damping force to be generated based on the steering stability control command (roll control command). The command current value calculation unit 25 is provided with, for example, a damping force map that shows the relationship between the "command current (damper command current) to be output to the damping force adjuster (e.g., solenoid) of the shock absorber 6, 8" and the "steering stability control command (roll control command)." That is, the command current value calculation unit 25 calculates the command current (damper command current) from the steering stability control command (roll control command) using the damping force map. The command current value calculation unit 25 outputs the calculated command current (damper command current) to the damping force adjuster (e.g., solenoid) of the shock absorber 6, 8. The shock absorber 6, 8 generates a damping force based on the damper command current from the suspension control device 21.

[0029] For example, when the damping force of the shock absorbers 6, 8 is used to decelerate the motion (behavior) of the sprung vehicle body 2, the suspension control device 21 increases the damping force of the shock absorbers 6, 8, and when the damping force of the shock absorbers 6, 8 is used to accelerate the motion (behavior) of the sprung vehicle body 2, the suspension control device 21 reduces the damping force of the shock absorbers 6, 8. In this way, the suspension control device 21 suppresses, for example, the roll behavior of the vehicle 1 and improves the handling stability of the vehicle body 2.

[0030] 1, the vehicle 1 is equipped with a steering device 10 (hereinafter referred to as the steering device 10) that steers the front wheels 3, 3 that are steered wheels (steered wheels). The steering device 10, also called a steering device, applies a steering angle to the front wheels 3, 3 in response to the operation of a steering wheel 11. The steering device 10 of the first embodiment is a steer-by-wire (SBW) system, that is, a steering system that steers the front wheels 3, 3 using an electric signal without mechanically connecting the steering wheel 11 operated by the driver to the front wheels 3, 3 that are steered wheels.

[0031] The steering device 10 includes, for example, a steering wheel 11 as a steering member, a steering angle sensor 12, a reaction force motor 13 as a reaction force actuator, a steering mechanism 14, a steering motor 15 as a steering actuator, an actual steering angle sensor 16, and a steer-by-wire control device 17 (hereinafter referred to as SBW control device 17) as a steering control device. The steering wheel 11 is operated by a driver. Note that the steering member of the vehicle 1 may be a steering member other than the steering wheel 11, such as a lever, a stick, or a gripped device. The steering angle sensor 12 detects the steering angle (input steering angle, steering angle) input to the steering wheel 11 as the steering member. The steering angle sensor 12 is connected to the SBW control device 17.

[0032] The steering angle sensor 12 outputs the detected steering angle (input steering angle, steering angle, SBW steering angle) to the SBW control device 17. The reaction force motor 13 is an electric motor, and is connected to the SBW control device 17. The reaction force motor 13 is driven based on a command from the SBW control device 17, thereby applying a steering reaction force to the steering wheel 11. Although not shown, a torque sensor may be provided to detect the torque of the steering wheel 11, and the steering torque detected by this torque sensor may also be output to the SBW control device 17.

[0033] The steering mechanism 14 steers the front wheels 3, 3 that serve as steered wheels based on the drive of the steering motor 15. The steering motor 15 is an electric motor, and is connected to the SBW control device 17. The steering motor 15 applies a steering angle to the front wheels 3, 3 that serve as steered wheels by operating the steering mechanism 14 based on a command from the SBW control device 17. The actual steering angle sensor 16 detects the actual steering angle, which is the actual steering angle of the front wheels 3, 3 that serve as steered wheels.

[0034] The actual steering angle sensor 16 is connected to the SBW control device 17. The actual steering angle sensor 16 outputs the detected actual steering angle (steered angle) to the SBW control device 17. The steering device 10 may be provided with a clutch device 18 between the steering wheel 11 and the steering mechanism 14. The clutch device 18 can mechanically connect the steering wheel 11 and the steering mechanism 14 as necessary. The clutch device 18 may be omitted. In other words, the steering wheel 11 and the steering mechanism 14 may not be mechanically connected to each other. In the first embodiment, the steering wheel 11 and the steering mechanism 14 are not mechanically connected to each other.

[0035] The input side of SBW control device 17 is connected to steering angle sensor 12 and actual steering angle sensor 16. The output side of SBW control device 17 is connected to steering motor 15 and reaction force motor 13. SBW control device 17 is also connected to communication line 9 such as CAN. SBW control device 17 includes a microcomputer having a central processing unit (CPU), a storage device (memory), a control board, etc., a power supply circuit, and a drive circuit.

[0036] SBW control device 17 drives steering motor 15 and reaction motor 13 based on the operation of steering wheel 11 (i.e., the steering angle detected by steering angle sensor 12), the actual steering angle of front wheels 3, 3 (i.e., the actual steering angle detected by actual steering angle sensor 16), and the vehicle situation (e.g., vehicle speed). In this way, SBW control device 17 can apply a steering angle to front wheels 3, 3 and a steering reaction force to steering wheel 11 according to the operation of steering wheel 11 and the vehicle situation.

[0037] Such a steer-by-wire steering device 10 is capable of driving assistance control such as emergency avoidance. For example, Fig. 8 shows a technology for increasing yaw response and improving emergency avoidance performance using the SBW control device 17 of the steering device 10, i.e., a technology for controlling the steering amount of the steered wheels (front wheels 3, 3) using the difference between a reference value such as MFC (model following control) and an estimated value obtained from a vehicle model. In Fig. 8, a solid line 91 represents the trajectory of the automobile (vehicle 1) when emergency avoidance control (model following control) is performed, and a dashed line 92 represents the trajectory of the automobile (vehicle 1) when emergency avoidance control (model following control) is not performed. Also, in Fig. 8, the "steering angle" represents the steering angle of the steering wheel 11, and the "steering angle" represents the steered angle (actual steering angle) of the steered wheels (front wheels 3, 3).

[0038] In this case, solid line 93 corresponds to the characteristic of the change in the steering angle of steering wheel 11 over time, solid line 94 corresponds to the characteristic of the change in the steering angle over time when emergency avoidance control (model following control) is being performed, and dashed line 95 corresponds to the characteristic of the change in the steering angle over time when emergency avoidance control (model following control) is not being performed. Also, solid line 96 corresponds to the characteristic of the yaw rate when emergency avoidance control (model following control) is being performed, and dashed line 97 corresponds to the characteristic of the yaw rate when emergency avoidance control (model following control) is not being performed. As shown in Figure 8, in steer-by-wire steering device 10, a steering angle is applied to front wheels 3, 3 so as to quickly increase the yaw rate in response to an input of the steering angle of steering wheel 11, thereby making it possible to suppress delays in the start of movement of vehicle 1 in the steering direction and excessive cornering.

[0039] However, the suspension control device described in the aforementioned Patent Document 1 is based on the premise that a vehicle is equipped with a general steering device (a steering device in which the wheels and the steering wheel are mechanically connected). Therefore, for example, the suspension control cannot be performed sufficiently to suppress the roll of the vehicle body that occurs due to an external disturbance or intervention of steering angle control by steer-by-wire, and the roll rate may increase.

[0040] That is, as described above, FIG. 8 shows a technology for controlling the amount of steering of the steered wheels (front wheels 3, 3) in a steer-by-wire steering device 10 using the difference between a reference value, such as MFC (model following control), and an estimated value obtained from a vehicle model. The vehicle 1 shown by the solid line in FIG. 8 illustrates the operation of MFC (model following control), i.e., the control operation of suppressing delay in the start of movement of the vehicle 1 in the steering direction and suppressing over-turning by increasing the yaw response of the vehicle 1. Also, FIG. 8 shows the characteristics of the steering angle and the change in the turning angle over time due to MFC (model following control). As shown in FIG. 8, even if the steering angle is constant, MFC (model following control) intervenes to control the turning angle to a turning amount that suppresses the yaw rate. That is, when the steering angle of the steering wheel 11 is input (solid line 93), the MFC (model following control) changes the turning angle as shown by solid line 94, resulting in a change in the yaw rate as shown by solid line 96. This improves the yaw rate.

[0041] However, in such a case, conventional suspension control technology may result in a worsening of the roll rate. That is, conventional suspension control technology is unable to provide sufficient suspension control to suppress the roll of the vehicle body that occurs due to the intervention of steering angle control by steer-by-wire, and the roll rate may worsen. Therefore, in the first embodiment, the deterioration of the roll rate is suppressed by appropriately performing suspension control in accordance with MFC (model following control).

[0042] That is, in the first embodiment, when a vehicle equipped with a steer-by-wire system turns, a control amount for suppressing a roll amount predicted from a physical quantity that changes more quickly is determined. More specifically, when the vehicle turns, a physical quantity that changes more quickly out of lateral acceleration, steering angle, actual steering angle (steered angle), etc. is set as a value used for control (a value to follow), and a control amount for suppressing a roll amount predicted from this value is determined. This reduces the roll rate and improves handling stability (steering feel, roll sensation). These points will be described in detail below with reference to FIGS. 3 to 7 in addition to FIGS. 1, 2, and 8.

[0043] 3 to 7 show a suspension control device 21 of the first embodiment. In the first embodiment, the steering angle used for suspension control is the "steering angle of the steering wheel 11 (input steering angle)" and the "target steering amount (model steering angle serving as a standard steering angle) estimated from the steering angle of the steering wheel 11 (input steering angle)." The state quantities used for suspension control are the "lateral jerk (SBW steering angle estimated lateral jerk) based on the steering angle (input steering angle)" and the "lateral jerk (target lateral jerk) based on the target steering amount (model steering angle serving as a standard steering angle)." Of these, the lateral jerk that changes more quickly, more specifically, the larger lateral jerk, is used for roll control (anti-roll control).

[0044] To this end, as shown in Fig. 3, the suspension control device 21 includes a target steering amount calculation unit 31, a target lateral jerk calculation unit 32, a steer-by-wire steering angle estimated lateral jerk calculation unit 33 (hereinafter referred to as SBW steering angle estimated lateral jerk calculation unit 33), and a roll control unit 34. The target steering amount calculation unit 31, the target lateral jerk calculation unit 32, and the SBW steering angle estimated lateral jerk calculation unit 33 in Fig. 3 correspond to, for example, the state estimating unit 22 in Fig. 2. The roll control unit 34 in Fig. 3 corresponds to, for example, the handling stability control unit 24 in Fig. 2.

[0045] As shown in Figures 3 and 4, vehicle speed and steering angle (SBW steering angle) are input to target steering amount calculation unit 31. The steering angle is the steering angle of steer-by-wire steering wheel 11, i.e., the SBW steering angle. The SBW steering angle and vehicle speed can be acquired, for example, via a communication line 9 such as a CAN. Target steering amount calculation unit 31 calculates the target steering amount based on the vehicle speed and steering angle (SBW steering angle). In this case, target steering amount calculation unit 31 uses a vehicle model in MFC (model following control) to estimate the steering amount (target steering amount) required to change the current vehicle behavior to a desired future behavior. The target steering amount corresponds to a reference steering angle (model steering angle, target steering angle) that is a steering angle corresponding to a reference turning state of vehicle 1 (turning in model following control).

[0046] As shown in Fig. 4, the target steering amount calculation unit 31 includes a first-order delay system standard yaw rate calculation model unit 31A, an optimization gain calculation unit 31B, and a vehicle model unit 31C. The first-order delay system standard yaw rate calculation model unit 31A receives the vehicle speed and the steering angle (SBW steering angle). The first-order delay system standard yaw rate calculation model unit 31A calculates (estimates) a standard yaw rate that becomes the target yaw rate from the vehicle speed and the steering angle (SBW steering angle) using a first-order delay system standard yaw rate calculation model. The first-order delay system standard yaw rate calculation model unit 31A outputs the calculated target yaw rate (standard yaw rate) to the optimization gain calculation unit 31B. The target yaw rate (standard yaw rate) is input to the optimization gain calculation unit 31B. The vehicle model unit 31C also inputs the estimated sideslip angle, the estimated yaw rate, and the result of integrating the difference between the estimated yaw rate and the target yaw rate (standard yaw rate) to the optimization gain calculation unit 31B.

[0047] Vehicle model unit 31C receives the vehicle speed and the target steering amount output from optimization gain calculation unit 31B. Vehicle model unit 31C calculates an estimated sideslip angle and an estimated yaw rate using a vehicle model from the vehicle speed and target steering amount. Optimization gain calculation unit 31B multiplies the "target yaw rate (standard yaw rate)," the "estimated sideslip angle," the "estimated yaw rate," and the "integral value of the difference between the estimated yaw rate and the target yaw rate" by each optimization gain, and then adds them together to calculate the target steering amount. Optimization gain calculation unit 31B outputs the calculated target steering amount to vehicle model unit 31C and target lateral jerk calculation unit 32.

[0048] As shown in FIGS. 3 and 5, the target lateral jerk calculation unit 32 receives inputs of the vehicle speed and the target steering amount. The target lateral jerk calculation unit 32 calculates the target lateral jerk based on the vehicle speed and the target steering amount. That is, the target lateral jerk calculation unit 32 calculates (estimates) the lateral jerk (standard steering angle command value) based on the target steering amount (model steering angle serving as the standard steering angle). As shown in FIG. 5, the target lateral jerk calculation unit 32 includes a vehicle model unit 32A and a differentiation unit 32B. The vehicle model unit 32A receives inputs of the vehicle speed and the target steering amount. The vehicle model unit 32A calculates the target lateral acceleration (target lateral G) using a vehicle model from the vehicle speed and the target steering amount. The vehicle model unit 32A outputs the calculated target lateral acceleration to the differentiation unit 32B. The target lateral acceleration corresponds to the lateral acceleration that should occur in the future (target lateral acceleration). The differentiation unit 32B receives input of the target lateral acceleration. The differentiating unit 32B calculates a target lateral jerk (target lateral J) by differentiating the target lateral acceleration. The differentiating unit 32B outputs the calculated target lateral jerk to the roll control unit 34. The target lateral jerk corresponds to a desired lateral jerk in the future (target lateral jerk). As described in International Publication No. 2018 / 003828, the target lateral jerk calculating unit 32 may have a mechanism for compensating for dynamics from the steering amount of the vehicle (target steering amount) to the generation of lateral acceleration using a phase adjustment filter (for example, a second-order filter expressed by a second-order delay system equation).

[0049] As shown in Figures 3 and 6, the vehicle speed and steering angle (SBW steering angle) are also input to the SBW steering angle estimated lateral jerk calculation unit 33. The SBW steering angle estimated lateral jerk calculation unit 33 calculates the SBW steering angle estimated lateral jerk based on the vehicle speed and the steering angle (SBW steering angle). That is, the SBW steering angle estimated lateral jerk calculation unit 33 calculates (estimates) the lateral jerk (input steering angle command value) based on the steering angle (SBW steering angle) of the steer-by-wire steering wheel 11. As shown in Figure 6, the SBW steering angle estimated lateral jerk calculation unit 33 includes a vehicle model unit 33A and a differentiation unit 33B. The vehicle speed and steering angle (SBW steering angle) are input to the vehicle model unit 33A. The vehicle model unit 33A calculates an SBW steering angle estimated lateral acceleration (SBW steering angle estimated lateral G) using a vehicle model based on the vehicle speed and the steering angle (SBW steering angle).

[0050] The vehicle model unit 33A outputs the calculated SBW steering angle estimated lateral acceleration to the differentiation unit 33B. The SBW steering angle estimated lateral acceleration is input to the differentiation unit 33B. The differentiation unit 33B calculates the SBW steering angle estimated lateral jerk (SBW steering angle estimated lateral J) by differentiating the SBW steering angle estimated lateral acceleration. The differentiation unit 33B outputs the calculated SBW steering angle estimated lateral jerk to the roll control unit 34. The SBW steering angle estimated lateral jerk calculation unit 33 may have a mechanism for compensating for dynamics from the vehicle steering angle (SBW steering angle) to the generation of lateral acceleration using a phase adjustment filter (for example, a second-order filter expressed by a second-order delay system equation).

[0051] As shown in Figures 3 and 7, the vehicle speed, target lateral jerk, and SBW steering angle estimated lateral jerk are input to the roll control unit 34. The roll control unit 34 calculates a roll control command based on the vehicle speed, target lateral jerk, and SBW steering angle estimated lateral jerk. The roll control unit 34 includes a high select unit 34A, a control intervention threshold unit 34B, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E. The target lateral jerk and SBW steering angle estimated lateral jerk are input to the high select unit 34A. The high select unit 34A compares the target lateral jerk with the SBW steering angle estimated lateral jerk and outputs the larger lateral jerk to the control intervention threshold unit 34B. The lateral jerk output from the high select unit 34A to the control intervention threshold unit 34B corresponds to a lateral jerk that takes into account a target steering amount (a model steering angle that becomes a standard steering angle) estimated from the steering angle (SBW steering angle) of the steer-by-wire steering wheel 11, i.e., a target steering amount-considered lateral jerk (standard steering angle-considered lateral jerk). In the first embodiment, this target steering amount-considered lateral jerk is used for roll control (anti-roll control).

[0052] That is, the target steering amount considered lateral jerk is input from high select unit 34A to control intervention threshold unit 34B. When the target steering amount considered lateral jerk is equal to or less than the threshold (within the dead zone), control intervention threshold unit 34B outputs 0 to gain multiplication unit 34C, and when the target steering amount considered lateral jerk exceeds the threshold (dead zone), it outputs the target steering amount considered lateral jerk to gain multiplication unit 34C. The threshold value of control intervention threshold unit 34B is a threshold value for the "SBW steering angle estimated lateral jerk based on the SBW steering angle" and the "target lateral jerk based on the target steering amount estimated from the SBW steering angle," so the value can be reduced. This makes it possible to perform roll control (anti-roll control) that suppresses the lateral jerk (physical quantity) that changes more quickly between the lateral jerk based on a change in the SBW steering angle (SBW steering angle estimated lateral jerk) and the lateral jerk based on a change in the target steering amount (target lateral jerk).

[0053] The gain multiplication unit 34C receives as input the lateral jerk that has been threshold-processed (control intervention threshold processing, dead band processing) by the control intervention threshold unit 34B, i.e., the target steering amount-considered lateral jerk after threshold processing. The gain multiplication unit 34C calculates a roll control command (vehicle speed-considered before roll control command) by multiplying the target steering amount-considered lateral jerk after threshold processing by a gain. The gain multiplication unit 34C outputs the calculated roll control command (vehicle speed-considered before roll control command) to the multiplication unit 34E. The vehicle speed is input to the gain table 34D. The gain table 34D calculates a gain corresponding to the vehicle speed. For example, the gain table 34D calculates a gain proportional to the vehicle speed (the higher the vehicle speed, the larger the gain value). The gain table 34D outputs the calculated gain to the multiplication unit 34E.

[0054] The multiplication unit 34E receives a roll control command (pre-vehicle speed-considered roll control command) and a gain (gain corresponding to the vehicle speed). The multiplication unit 34E calculates a roll control command (post-vehicle speed-considered roll control command) by multiplying the roll control command (pre-vehicle speed-considered roll control command) by the gain (gain corresponding to the vehicle speed). The multiplication unit 34E outputs the calculated roll control command (post-vehicle speed-considered roll control command). For example, the multiplication unit 34E outputs the calculated roll control command (post-vehicle speed-considered roll control command) to the command current value calculation unit 25 ( FIG. 2 ). The command current value calculation unit 25 outputs a command current (damper command current) corresponding to the input roll control command to a damping force adjuster (e.g., a solenoid) of the shock absorber 6, 8.

[0055] As described above, according to the first embodiment, the suspension control device 21 includes a target steering amount calculation unit 31 that receives the SBW steering angle and vehicle speed as inputs, an SBW steering angle estimated lateral jerk calculation unit 33 that receives the same inputs, and a target lateral jerk calculation unit 32 that receives the target steering amount output from the target steering amount calculation unit 31 as input. The suspension control device 21 also includes a roll control unit 34 that receives the SBW steering angle estimated lateral jerk output from the SBW steering angle estimated lateral jerk calculation unit 33, the target lateral jerk output from the target lateral jerk calculation unit 32, and the vehicle speed as inputs. The steering device 10 of the vehicle 1 has a function, such as model following control (MFC), that controls the steering amount of the front wheels 3, 3 that are steered wheels using the difference between a reference value and an estimated value obtained from a vehicle model. That is, the steering device 10 performs model following control as shown in FIG. 8 .

[0056] Meanwhile, the roll control section 34 of the suspension control device 21 performs roll control (anti-roll control) by high-selecting the SBW steering angle estimated lateral jerk and the target lateral jerk. That is, the roll control section 34 high-selects the SBW steering angle estimated lateral jerk and the target lateral jerk, and performs roll control (anti-roll control) using the high-selected lateral jerk. This makes it possible to track a rapidly changing physical quantity (lateral jerk) and perform control that appropriately suppresses roll for the amount of roll predicted from the tracked value. This makes it possible to sufficiently perform suspension control that suppresses vehicle body roll that occurs due to external disturbances or intervention of steering angle control by steer-by-wire, thereby suppressing the roll rate.

[0057] As described above, according to the first embodiment, the suspension control device 21 serving as a suspension control mechanism controls the suspensions 5, 7 that are suspension devices of the vehicle 1. The vehicle speed is input to the suspension control device 21 via a communication line 9 such as a CAN. As a result, the suspension control device 21 has a speed acquisition unit that acquires the vehicle speed of the vehicle 1. The vehicle speed is also input to the roll control unit 34 of the suspension control device 21. As a result, the roll control unit 34 has a speed acquisition unit. The target lateral jerk is input to the roll control unit 34 from the target lateral jerk calculation unit 32, and the SBW steering angle estimated lateral jerk is input from the SBW steering angle estimated lateral jerk calculation unit 33. As a result, the roll control unit 34 has a steering angle command value acquisition unit that acquires steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk) corresponding to the steering angle of the vehicle 1 (reference steering angle, input steering angle).

[0058] In this case, the high select unit 34A of the roll control unit 34 receives an input of a "normative steering angle command value," which is a command value (steering angle command value) based on the "vehicle speed" and the "normative steering angle (target steering amount), which is a steering angle corresponding to a normative turning state of the vehicle 1 (turning under model following control)." In this way, the high select unit 34A has a normative steering angle command value acquisition unit that acquires the normative steering angle command value (target lateral jerk). In addition, the high select unit 34A of the roll control unit 34 receives an "input steering angle command value," which is a command value (steering angle command value) based on the "vehicle speed" and the "input steering angle (SBW steering angle), which is a steering angle input to the steering member (steering wheel 11) of the vehicle 1." In other words, the SBW steering angle estimated lateral jerk. In this way, the high select unit 34A has an input steering angle command value acquisition unit that acquires the input steering angle command value (SBW steering angle estimated lateral jerk). In this way, the high select unit 34A is configured to acquire multiple (two) steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk) from the reference steering angle command value acquisition unit and the input steering angle command value acquisition unit.

[0059] Furthermore, the high select unit 34A and the control intervention threshold unit 34B determine whether the multiple (two) acquired steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk) exceed the corresponding threshold values ​​(dead bands). That is, the high select unit 34A and the control intervention threshold unit 34B constitute a determination unit that determines whether the multiple acquired steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk) exceed the corresponding threshold values. The roll control unit 34, which includes the high select unit 34A and the control intervention threshold unit 34B, controls the suspensions 5, 7 by referring to the steering angle command value that the control intervention threshold unit 34B determines to have exceeded the threshold value (i.e., the target lateral jerk and the SBW steering angle estimated lateral jerk are high selected, and the lateral jerk that is determined to have exceeded the threshold value). As a result, the roll control unit 34 has a command value determination unit that controls the suspensions 5, 7 by referring to the steering angle command value (target lateral jerk or SBW steering angle estimated lateral jerk) that has been determined to have exceeded the threshold by the determination unit (high select unit 34A and control intervention threshold unit 34B).

[0060] In this case, if the command value determination unit determines that only one steering angle command value has exceeded the threshold, for example, if either the target lateral jerk or the SBW steering angle estimated lateral jerk is greater than the threshold of the control intervention threshold unit 34B, the command value determination unit references that value to control the suspensions 5, 7. Also, if the command value determination unit determines that two command values ​​have exceeded the threshold, for example, if both the target lateral jerk and the SBW steering angle estimated lateral jerk are greater than the threshold of the control intervention threshold unit 34B, the command value determination unit references the largest lateral jerk (steering angle command value) to control the suspensions 5, 7.

[0061] The vehicle 1 equipped with the suspension control device 21 also includes a steering device 10 as a steering device (steering device) that steers the front wheels 3, 3 that serve as steered wheels (steered wheels) of the vehicle 1. In this case, the steering device 10 is of a steer-by-wire type. The input steering angle input to the steering member of the vehicle 1 is a steering angle (SBW steering angle) resulting from the driver's steering operation of the steering wheel 11. Furthermore, the vehicle 1 equipped with the suspension control device 21 also includes, in addition to the steer-by-wire type steering device, a function that controls the steering amount of the steered wheels (front wheels 3, 3) using the difference between a reference value, such as model following control (MFC), and an estimated value obtained from a vehicle model. This function may be, for example, a function that steers (controls) the steering amount of the steered wheels (front wheels 3, 3) using an advanced driver assistance system (ADAS) or autonomous driving (AD).

[0062] The roll control unit 34 of the suspension control device 21 also includes a high select unit 34A, a control intervention threshold unit 34B, and a multiplication unit 34E. The roll control unit 34 uses the high select unit 34A to high-select the target lateral jerk and the SBW steering angle estimated lateral jerk, and the control intervention threshold unit 34B determines whether the high-selected lateral jerk has exceeded a threshold (dead band). If it is determined that the high-selected lateral jerk has exceeded the threshold (dead band), a roll control command corresponding to this lateral jerk is output from the multiplication unit 34E of the roll control unit 34 to the command current value calculation unit 25. At this time, the multiplication unit 34E outputs, as a roll control command, a command including the result of multiplying the lateral jerk (target lateral jerk, SBW steering angle estimated lateral jerk) related to the input steering angle (SBW steering angle) by the vehicle speed, to the command current value calculation unit 25. The command current value calculation unit 25 supplies a damper command (current or voltage) corresponding to the roll control command to the damping force adjusting device (for example, solenoid) of the suspensions 5, 7 (shock absorbers 6, 8).

[0063] As a result, the suspension control device 21 is configured to start supplying current or voltage when the multiplication result of the input steering angle (SBW steering angle) and vehicle speed, more specifically, the multiplication result of the lateral jerk (target lateral jerk, SBW steering angle estimated lateral jerk) related to the input steering angle (SBW steering angle) and vehicle speed, is greater than a predetermined value. In this case, the predetermined value of the multiplication result can be set as the multiplication value of the lateral jerk threshold (threshold of the control intervention threshold unit 34B) and vehicle speed. This predetermined value corresponds to the threshold of the dead zone related to the input steering angle (SBW steering angle). In other words, this predetermined value does not correspond to the threshold of the dead zone related to the actual steering angle (actual steering angle) of the front wheels 3, 3, which are the steered wheels of the vehicle 1. For this reason, the predetermined value can be set to a small value.

[0064] In this way, the suspension control device 21 controls the suspensions 5, 7 (damping force adjusters of the shock absorbers 6, 8) by supplying current or voltage as a damper command from the suspension control device 21 to the suspensions 5, 7 (damping force adjusters of the shock absorbers 6, 8). In this case, the suspension control device 21 controls the suspensions 5, 7 of the vehicle 1 having the steer-by-wire steering device 10 by supplying current or voltage. The suspension control device 21 performs control processing including an input steering angle acquisition step, a vehicle speed acquisition step, and a power supply step.

[0065] The input steering angle acquisition step is a process of acquiring an input steering angle (SBW steering angle) input to a steering member (steering wheel 11) of the vehicle 1. The vehicle speed acquisition step is a process of acquiring the vehicle speed of the vehicle 1. The power supply step is executed after the input steering angle acquisition step and the vehicle speed acquisition step, and is a process of supplying current or voltage. In this case, the power supply step can start supplying current or voltage when the multiplication result (roll control command) of the input steering angle (SBW steering angle) and the vehicle speed is equal to or greater than a predetermined value. The predetermined value can be set to a small value (e.g., 0 or a value close to 0) by regarding all input steering angles (SBW steering angles) as representing the driver's intention. Furthermore, the predetermined value can be set to a small value (e.g., 0 or a value close to 0) by regarding all standard steering angles (target steering amounts) as equivalent to the driver's intention.

[0066] The input steering angle (SBW steering angle) in the power supply step may be expressed in units of, for example, radians (rad) or degrees (deg), or an angle converted to these. The vehicle speed in the power supply step may be expressed in units of, for example, meters per second (m / s), or a speed converted to these. The multiplication result in the power supply step may be the product of the input steering angle (SBW steering angle) and the vehicle speed itself, or a value including the product of the input steering angle (SBW steering angle) and the vehicle speed (a value related to the product of the input steering angle and the vehicle speed). The predetermined value of the multiplication result in the power supply step may be set as a threshold value (dead band threshold) for the product of the input steering angle and the vehicle speed itself, or as a threshold value (dead band threshold) for a value including the product of the input steering angle and the vehicle speed (a value related to the product of the multiplication).

[0067] When the multiplication result of the input steering angle (SBW steering angle) and the vehicle speed is used as the multiplication result of the power supply step, the predetermined value of the multiplication result of the power supply step (dead band threshold) can be expressed in units of radian meters per second (rad·m / s) or degree meters per second (deg·m / s). Also, the predetermined value of the multiplication result of the power supply step can be set to 0. In this case, the power supply step can start supplying current or voltage when the multiplication result is greater than the predetermined value of 0 radian meters per second (rad·m / s) or 0 degree meters per second (deg·m / s).

[0068] As described above, according to the first embodiment, the roll control unit 34 of the suspension control device 21 uses the high select unit 34A and the control intervention threshold unit 34B to determine whether multiple steering angle command values ​​(target lateral jerk and SBW steering angle estimated lateral jerk) exceed thresholds (dead bands). The target lateral jerk is a steering angle command value (standard steering angle command value) based on a standard steering angle (target steering amount) corresponding to a standard turning state of the vehicle 1 (turning under model following control). The SBW steering angle estimated lateral jerk is a steering angle command value (input steering angle command value) based on an input steering angle (SBW steering angle) input to the steering wheel 11, which is a steering member of the vehicle 1. The roll control unit 34 then controls the suspensions 5, 7 by referring to the steering angle command value (target lateral jerk or SBW steering angle estimated lateral jerk) that exceeds the threshold.

[0069] Therefore, the suspensions 5, 7 can be controlled by referring to the steering angle command value (target lateral jerk or SBW steering angle estimated lateral jerk) that exceeds the threshold value earlier among multiple steering angle command values ​​(target lateral jerk and SBW steering angle estimated lateral jerk). In other words, the steering angle (target steering amount or SBW steering angle) that changes more quickly can be used for suspension control. This makes it possible to advance the start timing of control (anti-roll control) of the suspensions 5, 7 and to intervene in the control at the necessary timing. This improves steering feel. Moreover, because the steering feel can be improved by setting the software, performance can be improved while suppressing increases in costs.

[0070] According to the first embodiment, the input steering angle input to the steering member of the vehicle 1 is the steering angle (SBW steering angle) resulting from the driver's steering operation on the steering wheel 11. Therefore, the suspensions 5, 7 can be controlled using a steering angle command value (SBW steering angle estimated lateral jerk) based on the steering angle (SBW steering angle) resulting from the driver's steering operation on the steering wheel 11. Also, according to the first embodiment, the steering device 10 that steers the front wheels 3, 3 that are the steerable wheels of the vehicle 1 is a steer-by-wire system. Therefore, the suspensions 5, 7 of the vehicle 1 equipped with the steer-by-wire steering device 10 can be controlled using a steering angle command value (SBW steering angle estimated lateral jerk) based on the steering angle (SBW steering angle) resulting from the driver's steering operation on the steering wheel 11.

[0071] According to the first embodiment, when the product of the input steering angle (SBW steering angle) input to the steering wheel 11 of the steer-by-wire vehicle 1 and the vehicle speed is greater than a predetermined value, the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. More specifically, the suspension control device 21 including the roll control unit 34 can start the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) when the product of the lateral jerk (target lateral jerk, SBW steering angle estimated lateral jerk) related to the input steering angle (SBW steering angle) and the vehicle speed is greater than a predetermined value. The predetermined value corresponds to a threshold value of the dead zone of the suspension control related to the steering angle (input steering angle, SBW steering angle) of the steering wheel 11. In other words, the predetermined value is not a threshold value of the dead zone of the suspension control related to the actual steering angle (actual steering angle) of the front wheels 3, 3, which are the steered wheels of the vehicle 1. For this reason, the predetermined value can be set to a small value. This allows the start timing of roll control (anti-roll control) of the suspensions 5 and 7 (shock absorbers 6 and 8) to be advanced, and control to be intervened at the necessary timing. As a result, steering feel can be improved. Moreover, because steering feel can be improved by setting the software, performance can be improved while suppressing cost increases.

[0072] According to the first embodiment, the steering angle of the steering wheel 11 (input steering angle, SBW steering angle) can be expressed in units of arc degrees [rad], degrees [deg], or an angle converted into these. The vehicle speed can be expressed in units of meters per second [m / s], or a speed converted into these. In this case, the predetermined value can be expressed in units of radian meters per second [rad m / s] or degree meters per second [deg m / s]. That is, the predetermined value can be set as a threshold value in units of radian meters per second [rad m / s] or degree meters per second [deg m / s].

[0073] According to the first embodiment, when the product of the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 and the vehicle speed is greater than a predetermined value of 0 radian meters per second (rad·m / s) or 0 degrees meters per second (deg·m / s), the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. That is, the "dead zone threshold (control intervention threshold) related to the steering angle (input steering angle, SBW steering angle) of the steering wheel 11" and / or the "dead zone threshold (control intervention threshold) related to the standard steering angle (target steering amount) corresponding to the standard turning state of the vehicle 1" can be set to 0. As a result, when the "steering angle (input steering angle, SBW steering angle)" and "vehicle speed" become greater than 0, the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. In this case, there is no dead zone threshold (control intervention threshold) for the suspensions 5, 7 (shock absorbers 6, 8) related to steering of the steering wheel 11, and if the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 changes, control of the suspensions 5, 7 (shock absorbers 6, 8) can always be intervened.

[0074] Furthermore, when the "standard steering angle (target steering amount)" and "vehicle speed" become greater than 0, the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. In this case, the dead zone threshold (control intervention threshold) of the suspensions 5, 7 (shock absorbers 6, 8) for the standard steering angle (model steering angle) disappears, and any change in the standard steering angle (model steering angle) can always cause the control of the suspensions 5, 7 (shock absorbers 6, 8) to intervene. In summary, in a steer-by-wire system, the steering wheel 11 and the front wheels 3, 3, which are the steered wheels, are not mechanically coupled (there is no shaft, for example, no intermediate shaft), so road surface input is not transmitted to the steering wheel 11. For this reason, input from the steering wheel 11 can be regarded as an intentional operation by the driver, and the control of the suspensions 5, 7 (shock absorbers 6, 8) can always be intervened. Furthermore, input from the standard steering angle can also be regarded as equivalent to an intentional operation by the driver, and the control of the suspensions 5, 7 (shock absorbers 6, 8) can always be intervened.

[0075] In the first embodiment, the target steering amount estimated from the steering angle of the steering wheel 11 is used as the standard steering angle (the steering angle corresponding to the standard turning state of the vehicle 1). However, this is not limiting. For example, as in a first modified example shown in FIGS. 9 to 11 , the standard steering angle (the steering angle corresponding to the standard turning state of the vehicle 1) may be a planned steering angle assigned based on a planned curvature (future curvature in the direction the vehicle will travel) and a planned vehicle speed (future vehicle speed) estimated from vehicle external environment information obtained from vehicle external environment information acquisition means such as LiDAR or GPS. The planned steering angle (standard steering angle, target steering angle) based on the planned curvature and the planned vehicle speed is used, for example, in an advanced driver assistance system (ADAS) or an autonomous driving (AD). In this case, the vehicle 1 of the first modified example has a function (steering function) of steering (controlling) the steered wheels (front wheels 3, 3) based on the standard steering angle (planned steering angle), as in the first embodiment.

[0076] That is, in the first modified example, the vehicle 1 is equipped with a vehicle external environment information acquisition means (not shown), such as LiDAR or GPS, that acquires vehicle external environment information, such as the surrounding conditions and position of the vehicle 1. From the vehicle external environment information, such as the surrounding conditions and position of the vehicle 1, a planned curvature, which is the future curvature of the vehicle 1, and a planned vehicle speed, which is the future vehicle speed of the vehicle 1, can be calculated (estimated). Then, based on the planned curvature and the planned vehicle speed, a planned steering angle (standard steering angle) corresponding to a reference turning state (planned turning state) of the vehicle 1 can be obtained. As shown in FIG. 9 , the planned curvature and the planned vehicle speed are input to the suspension control device 21 via a communication line 9, such as a CAN. The suspension control device 21 of the first modified example includes a planned lateral jerk calculation unit 41 instead of the target steering amount calculation unit 31 and the target lateral jerk calculation unit 32 of the first embodiment. That is, the suspension control device 21 includes an SBW steering angle estimated lateral jerk calculation unit 33, a planned lateral jerk calculation unit 41, and a roll control unit 42. The SBW steering angle estimated lateral jerk calculation unit 33 is the same as that in the first embodiment.

[0077] As shown in Figures 9 and 10, a planned curvature and a planned vehicle speed are input to the planned lateral jerk calculation unit 41. The planned lateral jerk calculation unit 41 calculates a planned lateral jerk (standard steering angle command value) from the planned curvature and the planned vehicle speed. In this case, the planned lateral jerk calculation unit 41 does not directly calculate a planned steering angle (standard steering angle), but the planned lateral jerk calculated from the planned curvature and the planned vehicle speed is equivalent to the planned lateral jerk calculated from the planned steering angle (standard steering angle). The planned lateral jerk calculation unit 41 includes a squaring unit 41A, a multiplication unit 41B, and a differentiation unit 41C. The squaring unit 41A and the multiplication unit 41B calculate the planned lateral acceleration based on the planned curvature and the planned vehicle speed. That is, the planned vehicle speed and the planned curvature are input to the squaring unit 41A and the multiplication unit 41B. Squaring unit 41A and multiplying unit 41B calculate a planned lateral acceleration by squaring the planned vehicle speed in squaring unit 41A and multiplying this squared planned vehicle speed by the planned curvature in multiplying unit 41B. The planned lateral acceleration calculated by squaring unit 41A and multiplying unit 41B is input from multiplying unit 41B to differentiating unit 41C. Differentiating unit 41C calculates a planned lateral jerk by differentiating the planned lateral acceleration and outputs the calculated planned lateral jerk to roll control unit 42. The planned lateral acceleration corresponds to a target lateral acceleration corresponding to the lateral acceleration that should be achieved in the future, and the planned lateral jerk corresponds to a target lateral jerk corresponding to the lateral jerk that should be achieved in the future. For example, if the target lateral acceleration calculated by vehicle model unit 32A of target lateral jerk calculation unit 32 is set to the first target lateral acceleration, and the target lateral jerk calculated by differentiation unit 32B is set to the first target lateral jerk, the planned lateral acceleration corresponds to the second target lateral acceleration, and the planned lateral jerk corresponds to the second target lateral jerk.

[0078] 9 and 11, in addition to the vehicle speed, the roll control unit 42 of the first modified example receives as input the planned lateral jerk from the planned lateral jerk calculation unit 41 and the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33. As shown in FIG. 11, the roll control unit 42 of the first modified example includes a high select unit 42A, a control intervention threshold unit 34B, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E, similar to the roll control unit 34 (FIG. 7) of the first embodiment. The high select unit 42A receives as input the planned lateral jerk from the planned lateral jerk calculation unit 41. The high select unit 42A also receives as input the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33. The high select unit 42A compares the planned lateral jerk with the SBW steering angle estimated lateral jerk and outputs the larger lateral jerk to the control intervention threshold unit 34B.

[0079] The lateral jerk output from the high select unit 42A to the control intervention threshold unit 34B corresponds to a lateral jerk that takes into account a planned steering angle (standard steering angle) based on the planned curvature and planned vehicle speed, i.e., a planned consideration lateral jerk (standard steering angle considered lateral jerk). In the first modified example, this planned consideration lateral jerk is used for roll control (anti-roll control). Note that the control intervention threshold unit 34B, gain multiplication unit 34C, gain table 34D, and multiplication unit 34E of the first modified example are the same as those in the first embodiment.

[0080] As described above, in the first modified example, the roll control unit 42 also determines whether the multiple steering angle command values ​​(planned lateral jerk and SBW steering angle estimated lateral jerk) exceed the threshold value (dead band) using the high select unit 42A and the control intervention threshold unit 34B. Therefore, the suspensions 5, 7 can be controlled by referring to the steering angle command value (planned lateral jerk or SBW steering angle estimated lateral jerk) that exceeds the threshold value earlier among the multiple steering angle command values ​​(planned lateral jerk and SBW steering angle estimated lateral jerk). In other words, the steering angle that changes earlier between the planned steering angle (nominal steering angle) based on the planned curvature and the planned vehicle speed and the SBW steering angle (input steering angle) can be used for suspension control. This allows the first modified example to improve steering feel, similar to the first embodiment.

[0081] In the first embodiment, the target steering amount is set as the standard steering angle, while in the first modified example, the planned steering angle based on the planned curvature and planned vehicle speed is set as the standard steering angle. In contrast, for example, as in a second modified example shown in FIGS. 12 and 13 , both the "target steering amount" and the "planned steering angle" may be set as the standard steering angle. That is, the "target steering amount calculation unit 31 and target lateral jerk calculation unit 32 of the first embodiment" and the "planned lateral jerk calculation unit 41 of the first modified example" can coexist. In this case, as shown in FIG. 12 , the suspension control device 21 includes a target steering amount calculation unit 31, a target lateral jerk calculation unit 32, an SBW steering angle estimated lateral jerk calculation unit 33, a planned lateral jerk calculation unit 41, and a roll control unit 43. The target steering amount calculation unit 31, the target lateral jerk calculation unit 32, and the SBW steering angle estimated lateral jerk calculation unit 33 are the same as those in the first embodiment. The planned lateral jerk calculation unit 41 is the same as that in the first modified example.

[0082] 12 and 13 , in addition to the vehicle speed, the roll control unit 43 of the second modified example receives as input the target lateral jerk (first target lateral jerk) from the target lateral jerk calculation unit 32, the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33, and the planned lateral jerk (second target lateral jerk) from the planned lateral jerk calculation unit 41. The roll control unit 43 includes a high select unit 43A, a control intervention threshold unit 34B, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E. The high select unit 43A receives as input the target lateral jerk from the target lateral jerk calculation unit 32. The high select unit 43A also receives as input the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33. The high select unit 43A also receives as input the planned lateral jerk from the planned lateral jerk calculation unit 41.

[0083] The high select unit 43A compares the target lateral jerk (first standard steering angle command value), the planned lateral jerk (second standard steering angle command value), and the SBW steering angle estimated lateral jerk (input steering angle command value), and outputs the largest lateral jerk (steering angle command value) to the control intervention threshold unit 34B. The lateral jerk output from the high select unit 43A to the control intervention threshold unit 34B corresponds to the lateral jerk that takes into account the first standard steering angle (target steering amount) and the second standard steering angle (planned steering angle based on the planned curvature and planned vehicle speed), i.e., the standard steering angle-considered lateral jerk. Note that the control intervention threshold unit 34B, gain multiplication unit 34C, gain table 34D, and multiplication unit 34E of the second modified example are the same as those of the first embodiment.

[0084] In this way, in the second modified example, the roll control unit 43 performs high select processing on the outputs of the "target steering amount calculation unit 31 and target lateral jerk calculation unit 32," the "output of the planned lateral jerk calculation unit 41," and the "output of the SBW steering angle estimated lateral jerk calculation unit 33." This allows the "target steering amount calculation unit 31 and target lateral jerk calculation unit 32" and the "planned lateral jerk calculation unit 41" to coexist.

[0085] That is, in the second modified example, the roll control unit 43 also uses the high select unit 43A and the control intervention threshold unit 34B to determine whether the multiple steering angle command values ​​(target lateral jerk, planned lateral jerk, and SBW steering angle estimated lateral jerk) exceed a threshold value (dead band). Therefore, the suspensions 5 and 7 can be controlled by referring to the steering angle command value (target lateral jerk, planned lateral jerk, or SBW steering angle estimated lateral jerk) that exceeds the threshold value earlier among the multiple steering angle command values ​​(target lateral jerk, planned lateral jerk, and SBW steering angle estimated lateral jerk). In other words, the steering angle that changes earlier among the planned steering angle (second standard steering angle), the target steering amount (first standard steering angle), and the SBW steering angle (input steering angle) can be used for suspension control. This also improves the steering feel in the second modified example.

[0086] In the first and second modified examples, the planned vehicle speed and planned curvature are described as examples in which they are acquired by vehicle environment information acquisition means such as LiDAR, GPS, etc. However, the vehicle environment information acquisition means is not limited to LiDAR and GPS, and vehicle environment information acquisition means other than LiDAR and GPS, such as a camera (monocular, stereo, etc.), map information, etc., may also be used.

[0087] 14 to 19 show a second embodiment. The second embodiment is characterized in that a lateral jerk (actual steering angle estimated lateral jerk) based on an actual steering angle, which is the actual steering angle of the steered wheels of the vehicle, is used for control (roll control). In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and their description will be omitted.

[0088] As shown in FIG. 14 , the suspension control device 21 includes a state estimator 22 and a suspension controller 51. The suspension controller 51 includes a ride comfort controller 52, a handling stability controller 24, a control command determiner 53, and a command current value calculator 25. The ride comfort controller 52 receives vehicle state information from the state estimator 22. The ride comfort controller 52 outputs a control command (ride comfort control command) for improving the ride comfort of the vehicle 1 based on the vehicle state information. The ride comfort controller 52 corresponds to a road surface input-considered sprung vibration damping controller 63 shown in FIGS. 15 and 17 (described later). The ride comfort controller 52 (road surface input-considered sprung vibration damping controller 63) calculates a ride comfort control command (sprung vibration damping control command) for suppressing vibration of the vehicle body 2 using a control law such as a skyhook control law, a BLQ control law (bilinear optimal control law), an LQ control law (linear quadratic optimal control), or an H∞ control law based on the vehicle state information. The ride comfort control unit 52 (road surface input consideration sprung vibration damping control unit 63 ) outputs the calculated ride comfort control command (sprung vibration damping control command) to the control command determination unit 53 .

[0089] The steering stability control unit 24 corresponds to, for example, a roll control unit 62 shown in FIGS. 15 and 18 , which will be described later. The steering stability control unit 24 (roll control unit 62) calculates a steering stability control command (roll control command) for improving the steering stability of the vehicle 1 (suppressing the roll behavior) based on vehicle state information. The steering stability control unit 24 (roll control unit 62) outputs the calculated steering stability control command (roll control command) to a control command determiner 53. A ride comfort control command (sprung mass damping control command) and a steering stability control command (roll control command) are input to the control command determiner 53. The control command determiner 53 corresponds to, for example, a high selector 64 shown in FIG. 15 , which will be described later. The control command determiner 53 (high selector 64) compares the ride comfort control command (sprung mass damping control command) with the steering stability control command (roll control command), and outputs the larger control command to the command current value calculator 25 as a final control command.

[0090] The command current value calculation unit 25 receives a final control command from the control command determination unit 53. Based on the final control command, the command current value calculation unit 25 calculates a command current (damper command current) corresponding to a command signal (control signal) for the damping force to be generated. For example, the command current value calculation unit 25 calculates the command current (damper command current) from the final control command using a damping force map. The command current value calculation unit 25 outputs the calculated command current (damper command current) to a damping force adjusting device (e.g., a solenoid) of the shock absorber 6, 8.

[0091] The technology described in the aforementioned Patent Document 1 is based on the premise that a vehicle is equipped with a general steering device (a steering device in which the wheels and steering wheel are mechanically connected). Therefore, for example, in order to suppress erroneous intervention due to input from the wheels, it is not possible to reduce the control intervention threshold of suspension control, and it may not be possible to reduce the roll rate. That is, the technology described in the aforementioned Patent Document 1 performs anti-roll control using a threshold (j1) corresponding to the lateral jerk caused by turning the vehicle (≒ steering input), but for the reasons described above, it is necessary to set the threshold (dead band) large. Therefore, it is possible that the control cannot intervene on gentle curves, and the roll rate cannot be reduced.

[0092] Therefore, in the second embodiment, by focusing on the steer-by-wire configuration, i.e., the fact that the steering wheel and wheels are not mechanically connected, the anti-roll control initiation threshold (dead zone threshold) is set to a very small value, and the curve over which the control can intervene is made larger. In other words, by focusing on the fact that input to the steering wheel is substantially unaffected by road surface input, all input to the steering wheel is considered to be intentional by the driver, and the dead zone (threshold) is made smaller. In this case, since there is no mechanical connection between the steering mechanism that applies a steering angle to the wheels and the steering wheel, the suspension control makes decisions using both the "actual steering angle corresponding to the steering angle of the wheels" and the "steering angle corresponding to the steering angle of the steering wheel."

[0093] In summary, in conventional steering systems, because the steering wheel and wheels are mechanically connected, rough road surfaces can cause the steering wheel to move. If unnecessary anti-roll control of the suspension is initiated in this situation, ride comfort deteriorates. To prevent this, that is, to prevent the deterioration of ride comfort due to unnecessary anti-roll control of the suspension, it is necessary to set a large threshold value (dead band). However, this may result in an inability to reduce the roll rate.

[0094] In contrast, in the second embodiment, in a vehicle equipped with steer-by-wire and semi-active suspension, the initiation threshold (dead band threshold) of anti-roll control for the semi-active suspension is set to a very small value. In this way, when steer-by-wire and semi-active suspension are combined, the control intervention threshold for the semi-active suspension can be set to a very small value. That is, in the case of steer-by-wire, the steering wheel and the wheels are not mechanically coupled, so there is no need to prevent erroneous intervention due to input from the wheels. This allows the control intervention threshold for the semi-active suspension to be set to a small value, optimizing the timing of control intervention. As a result, control can be initiated at an appropriate timing, improving handling stability (steering feel, roll sensation). These points will be described in detail below with reference to FIGS. 15 to 19 in addition to FIG. 14 .

[0095] 15 to 18 show a suspension control device 21 of a second embodiment. In the second embodiment, the steering angle used for suspension control is the "steering angle (input steering angle) of the steering wheel 11" and the "actual steering angle, which is the actual steering angle of the front wheels 3, 3 that are steered wheels of the vehicle 1." The state quantities used for suspension control are the "lateral jerk based on the steering angle (input steering angle) (SBW steering angle estimated lateral jerk)" and the "lateral jerk based on the actual steering angle (actual steering angle estimated lateral jerk)." Then, until the "lateral jerk based on the actual steering angle (actual steering angle estimated lateral jerk)" exceeds a predetermined threshold, the "lateral jerk based on the steering angle (input steering angle) (SBW steering angle estimated lateral jerk)" is used for roll control (anti-roll control). Note that in the second embodiment, the standard steering angle (target steering amount, planned steering angle, target steering angle) is not used, and therefore the vehicle 1 does not need to have a function (steering function) to steer (control) the steered wheels (front wheels 3, 3) based on the standard steering angle.

[0096] As shown in Fig. 15, the suspension control device 21 includes an SBW steering angle estimated lateral jerk calculation unit 33, an actual steering angle estimated lateral jerk calculation unit 61, a roll control unit 62, a road surface input considered sprung vibration damping control unit 63, and a high select unit 64. The SBW steering angle estimated lateral jerk calculation unit 33 and the actual steering angle estimated lateral jerk calculation unit 61 in Fig. 15 correspond to, for example, the state estimator 22 in Fig. 14. The roll control unit 62 in Fig. 15 corresponds to, for example, the handling stability control unit 24 in Fig. 14. The road surface input considered sprung vibration damping control unit 63 in Fig. 15 corresponds to, for example, the ride comfort control unit 52 in Fig. 14. The high select unit 64 in Fig. 15 corresponds to, for example, the control command determiner 53 in Fig. 14.

[0097] As shown in Figures 15 and 16, the vehicle speed and the steering angle are input to the steering angle estimated lateral jerk calculation unit 61. The steering angle is the actual steering angle of the front wheels 3, 3, which are steered wheels of the vehicle 1. The steering angle can be acquired, together with the SBW steering angle and vehicle speed, through a communication line 9 such as a CAN. The steering angle estimated lateral jerk calculation unit 61 calculates the steering angle estimated lateral jerk based on the vehicle speed and the steering angle. In other words, the steering angle estimated lateral jerk calculation unit 61 calculates (estimates) the lateral jerk (steering angle command value) based on the steering angle of the front wheels 3, 3, to which a steering angle is applied by the steer-by-wire steering device 10. As shown in Figure 16, the steering angle estimated lateral jerk calculation unit 61 includes a vehicle model unit 61A and a differentiation unit 61B. The vehicle speed and the steering angle are input to the vehicle model unit 61A. The vehicle model unit 61A calculates the actual steering angle estimated lateral acceleration using a vehicle model based on the vehicle speed and the actual steering angle.

[0098] The vehicle model unit 61A outputs the calculated steering angle estimated lateral acceleration to the differentiation unit 61B. The steering angle estimated lateral acceleration is input to the differentiation unit 61B. The differentiation unit 61B calculates the steering angle estimated lateral jerk by differentiating the steering angle estimated lateral acceleration. The differentiation unit 61B outputs the calculated steering angle estimated lateral jerk to the roll control unit 62. Note that the steering angle estimated lateral jerk calculation unit 61 may have a mechanism for compensating for dynamics from the steering angle of the vehicle to the generation of lateral acceleration using a phase adjustment filter (for example, a second-order filter expressed by a second-order delay system equation).

[0099] As shown in Figures 15 and 17, various signals for sprung vibration damping control (sprung vibration damping control signals) are input to the road surface input consideration sprung vibration damping control unit 63. The sprung vibration damping control signals are signals used for sprung vibration damping control, such as signals corresponding to sprung vertical acceleration. The sprung vibration damping control signals can be acquired, along with the SBW steering angle, actual steering angle, and vehicle speed, via a communication line 9 such as a CAN. As shown in Figure 17, the road surface input consideration sprung vibration damping control unit 63 includes a sprung vibration damping control unit 63A. The road surface input consideration sprung vibration damping control unit 63 (sprung vibration damping control unit 63A) calculates a sprung vibration damping control command based on the sprung vibration damping control signals, i.e., various state quantities (sprung vertical acceleration, etc.) used for sprung vibration damping control. For example, the road surface input consideration sprung vibration damping control unit 63 (sprung vibration damping control unit 63A) calculates a sprung vibration damping control command from the group of sprung vibration damping control signals using a control law such as a skyhook control law, a BLQ control law (bilinear optimal control law), an LQ control law (linear quadratic optimal control), an H∞ control law, etc. The road surface input consideration sprung vibration damping control unit 63 (sprung vibration damping control unit 63A) outputs the calculated sprung vibration damping control command to the high select unit 64.

[0100] 15 and 18, the vehicle speed, the actual steering angle estimated lateral jerk, and the SBW steering angle estimated lateral jerk are input to the roll control unit 62. The roll control unit 62 calculates a roll control command based on the vehicle speed, the actual steering angle estimated lateral jerk, and the SBW steering angle estimated lateral jerk. The roll control unit 62 outputs the calculated roll control command to the high select unit 64. The roll control unit 62 includes an SBW steering angle control intervention threshold unit 62A as an input steering angle control intervention threshold unit, an actual steering angle control intervention threshold unit 62B, a comparison unit 62C, a threshold unit 62D, a switch unit 62E, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E.

[0101] The SBW steering angle control intervention threshold unit 62A receives the SBW steering angle estimated lateral jerk. When the SBW steering angle estimated lateral jerk is equal to or less than the SBW steering angle threshold (within the dead zone), the SBW steering angle control intervention threshold unit 62A outputs 0 to the switch unit 62E, and when the SBW steering angle estimated lateral jerk exceeds the SBW steering angle threshold (dead zone), the SBW steering angle estimated lateral jerk is output to the switch unit 62E. The SBW steering angle threshold is a threshold for the SBW steering angle estimated lateral jerk based on the SBW steering angle, so its value can be reduced. For example, the SBW steering angle control intervention threshold unit 62A can have the same configuration (same threshold) as the control intervention threshold unit 34B of the first embodiment.

[0102] The steering angle estimated lateral jerk is input to the steering angle control intervention threshold unit 62B. When the steering angle estimated lateral jerk is equal to or less than the steering angle threshold (within the dead band), the steering angle control intervention threshold unit 62B outputs 0 to the switch unit 62E, and when the steering angle estimated lateral jerk exceeds the steering angle threshold (dead band), the steering angle estimated lateral jerk is output to the switch unit 62E. The threshold (dead band) of the steering angle control intervention threshold unit 62B, i.e., the steering angle threshold, is greater than the threshold (dead band) of the SBW steering angle control intervention threshold unit 62A, i.e., the SBW steering angle threshold. For example, in order to suppress erroneous intervention due to input from the wheels (road surface input), the steering angle threshold is greater than the SBW steering angle threshold.

[0103] The comparison unit 62C receives the pivot angle estimated lateral jerk as an input. The comparison unit 62C also receives a switch switching threshold from the threshold unit 62D. The threshold (switch switching threshold) of the threshold unit 62D is set to, for example, the threshold (pivot angle threshold) of the pivot angle control intervention threshold unit 62B. The threshold (switch switching threshold) of the threshold unit 62D may be set to a value greater than the threshold (pivot angle threshold) of the pivot angle control intervention threshold unit 62B. The comparison unit 62C compares the threshold (switch switching threshold) of the threshold unit 62D with the pivot angle estimated lateral jerk, and outputs to the switch unit 62E whether the pivot angle estimated lateral jerk has exceeded the threshold (switch switching threshold).

[0104] The switch unit 62E receives an SBW steering angle estimated lateral jerk (0 or SBW steering angle estimated lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the SBW steering angle control intervention threshold unit 62A. The switch unit 62E also receives an actual steering angle estimated lateral jerk (0 or actual steering angle estimated lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the actual steering angle control intervention threshold unit 62B. The switch unit 62E also receives an input from the comparison unit 62C indicating whether the actual steering angle estimated lateral jerk has exceeded the threshold (switch changeover threshold) of the threshold unit 62D. If the actual steering angle estimated lateral jerk has not exceeded the threshold (switch changeover threshold), the switch unit 62E outputs the SBW steering angle estimated lateral jerk to the gain multiplication unit 34C. When the pivot angle estimated lateral jerk exceeds a threshold value (switch changeover threshold value), the switch unit 62E outputs the pivot angle estimated lateral jerk to the gain multiplication unit 34C. As a result, until the pivot angle estimated lateral jerk exceeds the threshold value (switch changeover threshold value), the SBW pivot angle estimated lateral jerk is output from the switch unit 62E to the gain multiplication unit 34C.

[0105] A sprung vibration damping control command is input to the high select unit 64 from the road surface input consideration sprung vibration damping control unit 63 (sprung vibration damping control unit 63A). A roll control command is also input to the high select unit 64 from the roll control unit 62. The high select unit 64 compares the sprung vibration damping control command with the roll control command, and outputs the larger command as a final control command to the command current value calculation unit 25. The command current value calculation unit 25 outputs a command current (damper command current) corresponding to the input final control command to the damping force adjusters (for example, solenoids) of the shock absorbers 6, 8.

[0106] As described above, according to the second embodiment, the suspension control device 21 includes an actual steering angle estimated lateral jerk calculation unit 61 that receives as input the actual steering angle and vehicle speed, and an SBW steering angle estimated lateral jerk calculation unit 33 that receives as input the steering angle (SBW steering angle) and vehicle speed. The suspension control device 21 also includes a roll control unit 62 that receives as input the actual steering angle estimated lateral jerk output from the actual steering angle estimated lateral jerk calculation unit 61, the SBW steering angle estimated lateral jerk output from the SBW steering angle estimated lateral jerk calculation unit 33, and other roll control signals. In the second embodiment, the other roll control signals correspond to a vehicle speed signal, but are not limited to a vehicle speed signal and may be signals of physical quantities that can be calculated in the same manner as when the vehicle speed is input. For example, the other roll control signals may be signals of the roll angle, roll rate, etc. of the vehicle body.

[0107] The suspension control device 21 also has a road surface input-considered sprung vibration damping control unit 63, which performs control that takes into account road surface input components such as kickback due to road surface input of the actual steering angle. The roll control unit 62 then performs roll control using the SBW steering angle estimated lateral jerk until the actual steering angle estimated lateral jerk exceeds a threshold (switch-over threshold), and then performs roll control using the actual steering angle estimated lateral jerk once the actual steering angle estimated lateral jerk exceeds the threshold (switch-over threshold). Furthermore, the suspension control device 21 controls the suspensions 5, 7 (shock absorbers 6, 8) using a final control command that is a high selection of the roll control command output from the roll control unit 62 and the sprung vibration damping control command output from the road surface input-considered sprung vibration damping control unit 63. This allows the roll rate of the vehicle 1 to be reduced without reducing the function of the road surface input-considered sprung vibration damping control unit 63.

[0108] As described above, according to the second embodiment, the vehicle speed of the vehicle 1 is input to the roll control unit 62 of the suspension control device 21. As a result, the roll control unit 62 has a speed acquisition unit that acquires the vehicle speed of the vehicle 1. The roll control unit 62 also receives the actual steering angle estimated lateral jerk from the actual steering angle estimated lateral jerk calculation unit 61 and the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33. As a result, the roll control unit 62 has a steering angle command value acquisition unit that acquires steering angle command values ​​(actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk) corresponding to the steering angle (actual steering angle, input steering angle) of the vehicle 1. In this case, the actual steering angle control intervention threshold unit 62B of the roll control unit 62 receives an "actual steering angle command value" that is a command value (steering angle command value) based on the "vehicle speed" and the "actual steering angle that is the actual steering angle of the steered wheels (front wheels 3, 3) of the vehicle 1," i.e., the actual steering angle estimated lateral jerk. As a result, the steering angle control intervention threshold unit 62B has an actual steering angle command value acquisition unit that acquires an actual steering angle command value (actual steering angle estimated lateral jerk). Also, the SBW steering angle control intervention threshold unit 62A of the roll control unit 62 receives an "input steering angle command value," which is a command value (steering angle command value) based on the "vehicle speed" and the "input steering angle (SBW steering angle), which is the steering angle input to the steering member (steering wheel 11) of the vehicle 1," i.e., the SBW steering angle estimated lateral jerk. As a result, the SBW steering angle control intervention threshold unit 62A has an input steering angle command value acquisition unit that acquires the input steering angle command value (SBW steering angle estimated lateral jerk). In this way, the roll control unit 62 is configured to acquire multiple (two) steering angle command values ​​(actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk) from the reference steering angle command value acquisition unit and the input steering angle command value acquisition unit.

[0109] Furthermore, the control intervention threshold unit 62B for actual steering angle and the control intervention threshold unit 62A for SBW steering angle determine whether or not the acquired multiple (two) steering angle command values ​​(actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk) have exceeded their corresponding thresholds (dead bands). That is, the control intervention threshold unit 62B for actual steering angle and the control intervention threshold unit 62A for SBW steering angle constitute determination units that determine whether or not the acquired multiple (two) steering angle command values ​​(actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk) have exceeded their corresponding thresholds (actual steering angle threshold, SBW steering angle threshold).

[0110] The switch unit 62E of the roll control unit 62 outputs the SBW steering angle estimated lateral jerk to the gain multiplication unit 34C until the actual steering angle estimated lateral jerk exceeds a threshold value (switch changeover threshold value), and outputs the actual steering angle estimated lateral jerk to the gain multiplication unit 34C when the actual steering angle estimated lateral jerk exceeds the threshold value (switch changeover threshold value). As a result, the roll control unit 62 has a command value determination unit that controls the suspensions 5, 7 by referring to the steering angle command values ​​(SBW steering angle estimated lateral jerk, actual steering angle estimated lateral jerk) that the determination units (actual steering angle control intervention threshold unit 62B and SBW steering angle control intervention threshold unit 62A) determine to have exceeded the threshold values ​​(actual steering angle threshold value, SBW steering angle threshold value).

[0111] In this case, if the command value determination unit determines that only one steering angle command value has exceeded the threshold, for example, if either the SBW steering angle estimated lateral jerk or the actual steering angle estimated lateral jerk is greater than the corresponding threshold (threshold for actual steering angle, threshold for SBW steering angle), it references that value to control the suspensions 5, 7. Also, if the command value determination unit determines that two command values ​​have exceeded the threshold, for example, if both the SBW steering angle estimated lateral jerk and the actual steering angle estimated lateral jerk are greater than the corresponding threshold (threshold for actual steering angle, threshold for SBW steering angle), it references the largest steering angle command value (lateral jerk) to control the suspensions 5, 7.

[0112] Furthermore, according to the second embodiment, the roll control unit 62 acquires the input steering angle command value (SBW steering angle estimated lateral jerk) and the actual steering angle command value (actual steering angle estimated lateral jerk). In this case, among the thresholds (actual steering angle threshold, SBW steering angle threshold) used by the determination units (actual steering angle control intervention threshold unit 62B and SBW steering angle control intervention threshold unit 62A), the threshold (actual steering angle threshold) corresponding to the actual steering angle command value (actual steering angle estimated lateral jerk) is larger than the threshold (SBW steering angle threshold) corresponding to the input steering angle command value (SBW steering angle estimated lateral jerk).

[0113] Further, roll control unit 62 is equipped with a control intervention threshold unit for actual steering angle 62B, a control intervention threshold unit for SBW steering angle 62A, and a switch unit 62E. Roll control unit 62 switches between the actual steering angle estimated lateral jerk that has exceeded the actual steering angle threshold in actual steering angle control intervention threshold unit 62B and the SBW steering angle estimated lateral jerk that has exceeded the SBW steering angle threshold in SBW steering angle control intervention threshold unit 62A, using switch unit 62E. At this time, switch unit 62E outputs the SBW steering angle estimated lateral jerk to gain multiplication unit 34C until the actual steering angle estimated lateral jerk exceeds the threshold (switch switching threshold), and outputs the actual steering angle estimated lateral jerk to gain multiplication unit 34C when the actual steering angle estimated lateral jerk exceeds the threshold (switch switching threshold). As a result, the multiplication unit 34E of the roll control unit 34 outputs to the command current value calculation unit 25 a roll control command corresponding to the lateral jerk output from the switch unit 62E.

[0114] At this time, the multiplication unit 34E outputs a command including the multiplication result of the lateral jerk (SBW steering angle estimated lateral jerk) related to the input steering angle (SBW steering angle) and the vehicle speed as a roll control command to the command current value calculation unit 25. The command current value calculation unit 25 supplies a damper command (current or voltage) corresponding to the roll control command to the damping force adjusters (e.g., solenoids) of the suspensions 5, 7 (shock absorbers 6, 8). As a result, the suspension control device 21 is configured to start supplying current or voltage when the multiplication result of the input steering angle (SBW steering angle) and the vehicle speed, more specifically, the multiplication result of the lateral jerk (SBW steering angle estimated lateral jerk) based on the input steering angle (SBW steering angle) and the vehicle speed, is greater than a predetermined value. In this case, the predetermined value of the multiplication result can be set as the product of the threshold value (SBW steering angle threshold value) of the lateral jerk (SBW steering angle estimated lateral jerk) based on the input steering angle (SBW steering angle) and the vehicle speed. This predetermined value corresponds to the threshold of the dead zone related to the input steering angle (SBW steering angle). In other words, this predetermined value does not correspond to the threshold of the dead zone related to the actual steering angle (actual steering angle) of the front wheels 3, 3, which are the steered wheels of the vehicle 1. For this reason, the predetermined value can be set to a small value.

[0115] In this way, the suspension control device 21 controls the suspensions 5, 7 (damping force adjusters of the shock absorbers 6, 8) by supplying current or voltage as a damper command from the suspension control device 21 to the suspensions 5, 7 (damping force adjusters of the shock absorbers 6, 8). In this case, the suspension control device 21 controls the suspensions 5, 7 of the vehicle 1 having the steer-by-wire steering device 10 by supplying current or voltage. The suspension control device 21 performs control processing including an input steering angle acquisition step, a vehicle speed acquisition step, and a power supply step.

[0116] The input steering angle acquisition step is a process of acquiring the input steering angle (SBW steering angle) input to the steering member (steering wheel 11) of the vehicle 1. The vehicle speed acquisition step is a process of acquiring the vehicle speed of the vehicle 1. The power supply step is executed after the input steering angle acquisition step and the vehicle speed acquisition step, and is a process of supplying current or voltage. In this case, the power supply step can start supplying current or voltage when the multiplication result (roll control command) of the input steering angle (SBW steering angle) and the vehicle speed is equal to or greater than a predetermined value. The predetermined value can be set to a small value (for example, 0 or a value close to 0) by considering all input steering angles (SBW steering angles) to be the driver's intention.

[0117] The input steering angle (SBW steering angle) in the power supply step may be expressed in units of, for example, radians (rad) or degrees (deg), or an angle converted to these. The vehicle speed in the power supply step may be expressed in units of, for example, meters per second (m / s), or a speed converted to these. The multiplication result in the power supply step may be the product of the input steering angle (SBW steering angle) and the vehicle speed itself, or a value including the product of the input steering angle (SBW steering angle) and the vehicle speed (a value related to the product of the input steering angle and the vehicle speed). The predetermined value of the multiplication result in the power supply step may be set as a threshold value (dead band threshold) for the product of the input steering angle and the vehicle speed itself, or as a threshold value (dead band threshold) for a value including the product of the input steering angle and the vehicle speed (a value related to the product of the multiplication).

[0118] When the multiplication result of the input steering angle (SBW steering angle) and the vehicle speed is used as the multiplication result of the power supply step, the predetermined value of the multiplication result of the power supply step (dead band threshold) can be expressed in units of radian meters per second (rad·m / s) or degree meters per second (deg·m / s). Also, the predetermined value of the multiplication result of the power supply step can be set to 0. In this case, the power supply step can start supplying current or voltage when the multiplication result is greater than the predetermined value of 0 radian meters per second (rad·m / s) or 0 degree meters per second (deg·m / s).

[0119] As described above, according to the second embodiment, the roll control unit 62 of the suspension control device 21 determines whether the multiple steering angle command values ​​(the steering angle estimated lateral jerk and the SBW steering angle estimated lateral jerk) exceed thresholds (dead bands) using the steering angle control intervention threshold unit 62B and the SBW steering angle control intervention threshold unit 62A. The steering angle estimated lateral jerk is a steering angle command value (steering angle command value) based on the steering angle, which is the actual steering angle of the front wheels 3, 3, which are the steered wheels of the vehicle 1. The SBW steering angle estimated lateral jerk is a steering angle command value (input steering angle command value) based on the input steering angle (SBW steering angle) input to the steering wheel 11, which is a steering member of the vehicle 1. The roll control unit 62 then controls the suspensions 5, 7 by referring to the steering angle command value (the steering angle estimated lateral jerk or the SBW steering angle estimated lateral jerk) that exceeds the threshold.

[0120] Therefore, the suspensions 5, 7 can be controlled by referring to the steering angle command value (actual steering angle estimated lateral jerk or SBW steering angle estimated lateral jerk) that exceeds the threshold value earlier among the multiple steering angle command values ​​(actual steering angle estimated lateral jerk and SBW steering angle estimated lateral jerk). In this case, until the actual steering angle estimated lateral jerk exceeds the threshold value (switch change threshold), the suspensions 5, 7 can be controlled by referring to the SBW steering angle estimated lateral jerk that exceeds the threshold value (SBW steering angle threshold) earlier. In other words, the steering angle that changes earlier between the actual steering angle and the SBW steering angle (input steering angle) can be used for suspension control. Therefore, the start timing of control (anti-roll control) of the suspensions 5, 7 can be advanced and the control can be intervened at the necessary timing. This improves steering feel. Moreover, since the steering feel can be improved by setting the software, performance can be improved while suppressing an increase in cost.

[0121] FIG. 19 shows time variations in lateral acceleration, lateral jerk (lateral jerk), damper control command, and roll rate for the second embodiment (present example) and a comparative example (conventional example). In FIG. 19 , the solid line 98 in the lateral jerk (lateral jerk) column corresponds to the control intervention threshold (i.e., the SBW steering angle threshold) for the second embodiment (present example), and the dashed line 99 corresponds to the control intervention threshold (i.e., the actual steering angle threshold) for the comparative example (conventional example). Also, in FIG. 19 , the solid lines in the damper control command and roll rate columns correspond to the second embodiment (present example), and the dashed lines correspond to the comparative example (conventional example). As shown in FIG. 19 , the second embodiment (present example) can advance the start timing of control (e.g., anti-roll control) of the suspensions 5 and 7 and enable control intervention at the required timing. This reduces the roll rate.

[0122] According to the second embodiment, the steering angle control intervention threshold unit 62B and the SBW steering angle control intervention threshold unit 62A determine whether the SBW steering angle estimated lateral jerk (input steering angle command value) and the steering angle estimated lateral jerk (steering angle command value) exceed their corresponding thresholds (SBW steering angle threshold, steering angle threshold). In this case, the threshold (steering angle threshold) corresponding to the steering angle estimated lateral jerk (steering angle command value) is greater than the threshold (SBW steering angle threshold) corresponding to the SBW steering angle estimated lateral jerk (input steering angle command value). Therefore, the suspensions 5, 7 can be controlled with reference to the SBW steering angle estimated lateral jerk (input steering angle command value) until the steering angle estimated lateral jerk (steering angle command value) exceeds the threshold (steering angle command value or switch changeover threshold).

[0123] According to the second embodiment, when the product of the input steering angle (SBW steering angle) input to the steering wheel 11 of the steer-by-wire vehicle 1 and the vehicle speed is greater than a predetermined value, the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. More specifically, the suspension control device 21 including the roll control unit 62 can start the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) when the product of the lateral jerk (SBW steering angle estimated lateral jerk) based on the input steering angle (SBW steering angle) and the vehicle speed is greater than a predetermined value. The predetermined value corresponds to a threshold value of the dead band of the suspension control based on the steering angle (input steering angle, SBW steering angle) of the steering wheel 11. In this case, the predetermined value can be set to a small value by regarding the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 as corresponding to the driver's intention. This allows the start timing of roll control (anti-roll control) of the suspensions 5 and 7 (shock absorbers 6 and 8) to be advanced, and control to be intervened at the necessary timing. This improves steering feel. Moreover, because the steering feel can be improved by setting the software, performance can be improved while suppressing cost increases.

[0124] According to the second embodiment, the steering angle of the steering wheel 11 (input steering angle, SBW steering angle) can be expressed in units of arc degrees [rad], degrees [deg], or an angle converted into these. The vehicle speed can be expressed in units of meters per second [m / s], or a speed converted into these. In this case, the predetermined value can be expressed in units of radian meters per second [rad m / s] or degree meters per second [deg m / s]. That is, the predetermined value can be set as a threshold value in units of radian meters per second [rad m / s] or degree meters per second [deg m / s].

[0125] According to the second embodiment, when the product of the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 and the vehicle speed is greater than a predetermined value of 0 radian meters per second [rad·m / s] or 0 degrees meters per second [deg·m / s], the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. That is, the dead band threshold (control intervention threshold) related to the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 can be set to 0. As a result, when both the steering angle (input steering angle, SBW steering angle) and the vehicle speed are greater than 0, the supply of current or voltage to the suspensions 5, 7 (shock absorbers 6, 8) can be started. In this case, there is no dead zone threshold (control intervention threshold) for the suspensions 5, 7 (shock absorbers 6, 8) related to steering of the steering wheel 11, and if the steering angle (input steering angle, SBW steering angle) of the steering wheel 11 changes, that is, if there is a steering input, control of the suspensions 5, 7 (shock absorbers 6, 8) can be intervened without fail. That is, in the steer-by-wire system, the steering wheel 11 and the front wheels 3, 3, which are the steered wheels, are not mechanically coupled (there is no shaft, for example, no intermediate shaft), so road surface input is not transmitted to the steering wheel 11. For this reason, input from the steering wheel 11 is regarded as an intentional operation by the driver, and control of the suspensions 5, 7 (shock absorbers 6, 8) can be intervened without fail in response to the intentional operation by the driver.

[0126] In the second embodiment, the suspension control is described using the "actual steering angle (actual steering angle) of the front wheels 3, 3 that are steered wheels" and the "steering angle of the steering wheel 11 (input steering angle, SBW steering angle)." However, the present invention is not limited to this. For example, as in a third modified example shown in Figures 20 and 21, instead of the steering angle of the steering wheel 11 (input steering angle, SBW steering angle), a reference steering angle that is a steering angle corresponding to a reference turning state of the vehicle 1, specifically, a planned steering angle (target steering angle) that is assigned based on a planned curvature and a planned vehicle speed estimated from vehicle external environment information obtained from vehicle external environment information acquisition means such as LiDAR or GPS, may be used.

[0127] That is, in the third modified example, the vehicle 1 is equipped with a vehicle external environment information acquisition means (not shown), such as LiDAR or GPS, that acquires vehicle external environment information such as the situation around the vehicle 1 and its position. From the vehicle external environment information such as the situation around the vehicle 1 and its position, a planned curvature, which is the future curvature of the vehicle 1, and a planned vehicle speed, which is the future vehicle speed of the vehicle 1, can be calculated (estimated). Then, based on the planned curvature and the planned vehicle speed, a planned steering angle (standard steering angle) corresponding to a standard turning state (planned turning state) of the vehicle 1 can be obtained. In the third modified example, the vehicle 1 has a function (steering function) of steering (controlling) the steered wheels (front wheels 3, 3) based on the planned steering angle (standard steering angle).

[0128] As shown in Fig. 20, the planned curvature and planned vehicle speed are input to the suspension control device 21 via a communication line 9 such as a CAN. The suspension control device 21 of the third modified example includes a planned lateral jerk calculation unit 41 instead of the SBW steering angle estimated lateral jerk calculation unit 33 of the second embodiment. That is, the suspension control device 21 includes an actual steering angle estimated lateral jerk calculation unit 61, a planned lateral jerk calculation unit 41, a roll control unit 71, a road surface input considered sprung vibration damping control unit 63, and a high select unit 64. The actual steering angle estimated lateral jerk calculation unit 61, the road surface input considered sprung vibration damping control unit 63, and the high select unit 64 are the same as those in the second embodiment. Furthermore, the planned lateral jerk calculation unit 41 is the same as that in the first modified example.

[0129] 20 and 21, in addition to the vehicle speed, the roll control unit 71 of the third modified example receives as input the planned lateral jerk from the planned lateral jerk calculation unit 41 and the actual steering angle estimated lateral jerk from the actual steering angle estimated lateral jerk calculation unit 61. As shown in Fig. 21, the roll control unit 71 of the third modified example includes a planned steering angle control intervention threshold unit 71A as a reference steering angle control intervention threshold unit, an actual steering angle control intervention threshold unit 62B, a comparison unit 62C, a threshold unit 62D, a switch unit 62E, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E. The planned lateral jerk is input to the planned steering angle control intervention threshold unit 71A. The planned steering angle control intervention threshold unit 71A outputs 0 to the switch unit 62E when the planned lateral jerk is equal to or less than the planned steering angle threshold (within the dead zone), and outputs the planned lateral jerk to the switch unit 62E when the planned lateral jerk exceeds the planned steering angle threshold (dead zone). The planned steering angle threshold (standard steering angle threshold) is a threshold for the planned lateral jerk based on the planned steering angle (standard steering angle), so its value can be made small. Note that the actual steering angle control intervention threshold unit 62B, comparison unit 62C, threshold unit 62D, switch unit 62E, gain multiplication unit 34C, gain table 34D, and multiplication unit 34E of the third modified example are the same as those of the second embodiment.

[0130] As described above, in the third modified example, the roll control unit 71 also determines whether the multiple steering angle command values ​​(the steering angle estimated lateral jerk and the planned lateral jerk) exceed the thresholds (dead bands) using the actual steering angle control intervention threshold unit 62B and the planned steering angle control intervention threshold unit 71A. The roll control unit 71 then controls the suspensions 5, 7 by referring to the steering angle command value (the actual steering angle estimated lateral jerk or the planned lateral jerk) that exceeds the threshold earlier. In this case, until the actual steering angle estimated lateral jerk exceeds the threshold (the switch change threshold), the suspensions 5, 7 can be controlled by referring to the planned lateral jerk that exceeds the threshold (the planned steering angle threshold) earlier. In other words, the steering angle that changes earlier between the actual steering angle and the planned steering angle (standard steering angle) can be used for suspension control. As a result, the third modified example can also improve the steering feel, as in the second embodiment.

[0131] In the second embodiment, the steering angle (input steering angle, SBW steering angle) and the turning angle (actual steering angle) are used for suspension control, while in the third modified example, the planned steering angle (standard steering angle) and the turning angle (actual steering angle) are used for suspension control. In contrast, for example, as in a fourth modified example shown in FIGS. 22 and 23 , the steering angle (input steering angle, SBW steering angle), the planned steering angle (standard steering angle), and the turning angle (actual steering angle) may be used. That is, the "SBW steering angle estimated lateral jerk calculation unit 33 of the second embodiment" and the "planned lateral jerk calculation unit 41 of the third modified example" can coexist. In this case, as shown in FIG. 22 , the suspension control device 21 includes the SBW steering angle estimated lateral jerk calculation unit 33, the actual steering angle estimated lateral jerk calculation unit 61, the planned lateral jerk calculation unit 41, the roll control unit 72, the road surface input consideration sprung vibration damping control unit 63, and the high select unit 64. The SBW steering angle estimated lateral jerk calculation unit 33, the actual steering angle estimated lateral jerk calculation unit 61, the road surface input consideration sprung vibration damping control unit 63, and the high select unit 64 are the same as those in the second embodiment. The planned lateral jerk calculation unit 41 is the same as that in the third modified example.

[0132] 22 and 23, in addition to the vehicle speed and the actual steering angle estimated lateral jerk, the roll control unit 72 of the fourth modified example receives as input the SBW steering angle estimated lateral jerk from the SBW steering angle estimated lateral jerk calculation unit 33 and the planned lateral jerk from the planned lateral jerk calculation unit 41. The roll control unit 72 includes an SBW steering angle control intervention threshold unit 62A, a planned steering angle control intervention threshold unit 71A, a high select unit 72A, an actual steering angle control intervention threshold unit 62B, a comparison unit 62C, a threshold unit 62D, a switch unit 62E, a gain multiplication unit 34C, a gain table 34D, and a multiplication unit 34E. The SBW steering angle estimated lateral jerk (0 or SBW steering angle estimated lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the SBW steering angle control intervention threshold unit 62A is input to the high select unit 72A. Further, the high select unit 72A receives the planned lateral jerk (0 or planned lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the planned steering angle control intervention threshold unit 71A.

[0133] The high select unit 72A compares the "SBW steering angle estimated lateral jerk processed by a threshold value" with the "planned lateral jerk processed by a threshold value" and outputs the larger lateral jerk to the switch unit 62E. Note that the SBW steering angle control intervention threshold unit 62A, actual steering angle control intervention threshold unit 62B, comparison unit 62C, threshold unit 62D, switch unit 62E, gain multiplication unit 34C, gain table 34D, and multiplication unit 34E of the fourth modified example are the same as those of the second embodiment. The planned steering angle control intervention threshold unit 71A of the fourth modified example is the same as that of the third modified example.

[0134] As described above, in the fourth modified example, the roll control unit 72 performs high select processing on the outputs of the SBW steering angle estimated lateral jerk calculation unit 33 and the planned lateral jerk calculation unit 41, which are each subjected to threshold processing. This allows the SBW steering angle estimated lateral jerk calculation unit 33 and the planned lateral jerk calculation unit 41 to coexist. In this case, the roll control unit 72 determines whether or not multiple steering angle command values ​​(actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk, and planned lateral jerk) have exceeded thresholds (dead bands) using the actual steering angle control intervention threshold unit 62B, the SBW steering angle control intervention threshold unit 62A, and the planned steering angle control intervention threshold unit 71A. Then, the roll control unit 72 controls the suspensions 5, 7 by referring to the steering angle command value (actual steering angle estimated lateral jerk, SBW steering angle estimated lateral jerk, or planned lateral jerk) that exceeded the threshold earlier. In this case, until the actual steering angle estimated lateral jerk exceeds the threshold value (switch changeover threshold value), the suspensions 5, 7 can be controlled by referring to the lateral jerk (SBW steering angle estimated lateral jerk or planned lateral jerk) that exceeds the threshold value (SBW steering angle threshold value or planned steering angle threshold value) more quickly. In other words, the steering angle that changes more quickly among the actual steering angle, SBW steering angle (input steering angle), and planned steering angle (reference steering angle) can be used for suspension control. As a result, the fourth modified example can also improve the steering feel, as in the second embodiment.

[0135] In the third and fourth modified examples, the planned vehicle speed and planned curvature are described as examples in which they are acquired by vehicle environment information acquisition means such as LiDAR, GPS, etc. However, the vehicle environment information acquisition means is not limited to LiDAR and GPS, and vehicle environment information acquisition means other than LiDAR and GPS, such as a camera (monocular, stereo, etc.), map information, etc., may also be used.

[0136] As described above, the steering device 10 may be configured to have a clutch device 18 (FIG. 1) provided between the steering wheel 11 and the steering mechanism 14 as a redundant function. That is, the steering device 10 may be configured to switch from a steer-by steering system to a steering system in which the steering wheel 11 and the steering mechanism 14 are mechanically connected by connecting the clutch device 18 depending on the situation. In this case, for example, the suspension control device 21 may be configured to include a steering system determination unit 81, as in a fifth modified example shown in FIGS. 24 and 25 .

[0137] 24, the suspension control device 21 of the fifth modified example includes an SBW steering angle estimated lateral jerk calculation unit 33, an actual steering angle estimated lateral jerk calculation unit 61, a steering system determination unit 81, and a roll control unit 82. The SBW steering angle estimated lateral jerk calculation unit 33 and the actual steering angle estimated lateral jerk calculation unit 61 are the same as those in the second embodiment.

[0138] 24 and 25, the SBW valid flag, the SBW steering angle estimated lateral jerk, and the actual steering angle estimated lateral jerk are input to the steering system determination unit 81. The SBW valid flag can be acquired, together with the actual steering angle, the SBW steering angle, and the vehicle speed, through a communication line 9 such as a CAN. The SBW valid flag is output, for example, from the steering device 10. For example, when the SBW is valid (the clutch device 18 is disengaged), the steering device 10 outputs "1" as the SBW valid flag, and when the SBW is invalid (the clutch device 18 is engaged), the steering device 10 outputs "0" as the SBW valid flag. As a result, the SBW valid flag (1 or 0) corresponding to whether the SBW is valid or invalid (the clutch device 18 is disengaged or engaged) is input to the steering system determination unit 81.

[0139] The steering system determination unit 81 outputs a lateral jerk corresponding to whether SBW is enabled or disabled as a control lateral jerk to the roll control unit 82 based on the SBW enable flag, the SBW steering angle estimated lateral jerk, and the actual steering angle estimated lateral jerk. As shown in FIG. 25 , the steering system determination unit 81 includes a comparison unit 81A, a threshold unit 81B, and a switch unit 81C. The SBW enable flag is input to the comparison unit 81A. The comparison unit 81A also receives a switch switching threshold from the threshold unit 81B. The threshold (switch switching threshold) of the threshold unit 81B can be set to, for example, 0.5. The comparison unit 81A compares the switch switching threshold (0.5) of the threshold unit 81B with the SBW enable flag (1 or 0), and outputs to the switch unit 81C whether the SBW enable flag exceeds the switch switching threshold, i.e., whether SBW is enabled.

[0140] The switch unit 81C receives the SBW steering angle estimated lateral jerk (0 or SBW steering angle estimated lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the SBW steering angle control intervention threshold unit 62A. The switch unit 62E receives the actual steering angle estimated lateral jerk (0 or actual steering angle estimated lateral jerk) that has been subjected to threshold processing (control intervention threshold processing, dead band processing) by the actual steering angle control intervention threshold unit 62B. The switch unit 81C also receives an input from the comparison unit 81A indicating whether the SBW valid flag has exceeded the switch switching threshold. If the SBW valid flag has not exceeded the switch switching threshold, i.e., if the SBW valid flag is 0 and SBW is invalid, the switch unit 81C outputs the actual steering angle estimated lateral jerk to the roll control unit 82 as the control lateral jerk. When the SBW valid flag exceeds the switch changeover threshold, i.e., when the SBW valid flag is 1 and SBW is valid, switch unit 81C outputs the SBW steering angle estimated lateral jerk as the control lateral jerk to roll control unit 82. Roll control unit 82 calculates a roll control command based on the input control lateral jerk (SBW steering angle estimated lateral jerk when SBW is valid, and actual steering angle estimated lateral jerk when SBW is invalid) and vehicle speed. Roll control unit 82 outputs the calculated roll control command to command current value calculation unit 25 or control command determination unit 53 (high select unit 64).

[0141] In the case of this fifth modified example as well, the roll control unit 82 controls the suspensions 5, 7 by referring to the steering angle command value (actual steering angle estimated lateral jerk or SBW steering angle estimated lateral jerk) that exceeds a threshold value (actual steering angle threshold value or SBW steering angle threshold value). In this case, when SBW is enabled, the suspensions 5, 7 can be controlled by referring to the SBW steering angle estimated lateral jerk. In other words, when SBW is enabled, the steering angle that changes more quickly between the actual steering angle and the SBW steering angle (input steering angle) can be used for suspension control. This also makes it possible for the fifth modified example to improve steering feel.

[0142] 7, in the first embodiment described above, the target lateral jerk (standard steering angle command value) and the SBW steering angle estimated lateral jerk (input steering angle command value) are high selected by the high select unit 34A and then threshold processed (control intervention threshold processing, dead band processing) by the control intervention threshold unit 34B. However, the present invention is not limited to this. For example, the target lateral jerk and the SBW steering angle estimated lateral jerk may be threshold processed (control intervention threshold processing, dead band processing) with their respective corresponding thresholds before being high selected. That is, the target lateral jerk may be threshold processed by the target steering amount control intervention threshold unit (standard steering angle control intervention threshold unit) and the SBW steering angle estimated lateral jerk may be threshold processed by the SBW steering angle control intervention threshold unit (input steering angle control intervention threshold unit), and then these may be high selected by the high select unit. The former "high select unit 34A and control intervention threshold unit 34B" and the latter "target steering amount control intervention threshold unit (standard steering angle control intervention threshold unit), SBW steering angle control intervention threshold unit (input steering angle control intervention threshold unit) and high select unit" correspond to "determination units that determine whether the acquired multiple steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk) have exceeded the corresponding thresholds (control intervention thresholds)." This also applies to the second embodiment and each of the modified examples.

[0143] As shown in FIG. 13 , in the second modified example described above, a case has been described in which three steering angle command values ​​(target lateral jerk, SBW steering angle estimated lateral jerk, and planned lateral jerk) are high-selected and then threshold-value processed (control intervention threshold processing, dead-band processing). However, this is not limiting, and three standard steering angle command values ​​(lateral jerk) may be threshold-processed (control intervention threshold processing, dead-band processing) with corresponding thresholds before high-selection. That is, the determination unit that determines whether multiple steering angle command values ​​have exceeded their corresponding thresholds may be configured with a high select unit and a control intervention threshold unit, or may be configured with multiple control intervention threshold units and a high select unit. In either case, the command value determination unit that controls the suspension by referring to the steering angle command value (lateral jerk) can control the suspension by referring to that value when the determination unit determines that only one steering angle command value has exceeded a threshold. In addition, when the judgment unit judges that two or more command values ​​have exceeded the threshold, the command value determination unit can control the suspension by referring to the largest steering angle command value among the values.

[0144] 23, the fourth modified example has been described with reference to an example in which the roll control unit 72 is configured to receive a planned lateral jerk corresponding to a standard steering angle command value based on a standard steering angle, an actual steering angle estimated lateral jerk corresponding to an actual steering angle command value based on an actual steering angle, and an SBW steering angle estimated lateral jerk corresponding to an input steering angle command value based on an input steering angle. That is, the roll control unit 72 has a standard steering angle command value acquisition unit that acquires the standard steering angle command value, an input steering angle command value acquisition unit that acquires the input steering angle command value, and an actual steering angle command value acquisition unit that acquires the actual steering angle command value. Alternatively, as shown in the first embodiment (FIG. 7), the first modified example (FIG. 11), the second modified example (FIG. 13), the second embodiment (FIG. 18), and the third modified example (FIG. 22), the roll control unit may have at least two command value acquisition units selected from the standard steering angle command value acquisition unit, the input steering angle command value acquisition unit, and the actual steering angle command value acquisition unit. Although not shown in the drawings, the roll control unit may be configured to have more than three command value acquisition units. That is, the steering angle command value acquisition unit may be configured to acquire multiple steering angle command values ​​from a group including at least two of a reference steering angle command value acquisition unit, an input steering angle command value acquisition unit, and an actual steering angle command value acquisition unit.

[0145] Here, for example, consider a configuration having a "standard steering angle command value acquisition unit" and an "input steering angle command value acquisition unit." The standard steering angle command value acquired by the standard steering angle command value acquisition unit corresponds to a command value (target lateral jerk, planned lateral jerk) based on a standard steering angle (target steering amount, planned steering angle) provided by automatic steering control such as MFC (model following control), ADAS (advanced driver assistance system), or AD (autonomous driving). The input steering angle command value acquired by the input steering angle command value acquisition unit corresponds to a command value (SBW steering angle estimated lateral jerk) based on a steering angle (input steering angle) input to a steering member (e.g., steering wheel 11). In this case, if only one steering angle command value exceeds the threshold, suspension control (roll control) can be performed with reference to that value. If both steering angle command values ​​exceed the threshold, suspension control (roll control) can be performed with reference to the larger steering angle command value. For example, if MFC (model following control) is performed due to a sudden operation of the steering wheel 11 during normal driving, such as when merging into a traffic lane, suspension control (roll control) can be performed based on changes in the standard steering angle of this MFC (model following control).

[0146] Also, for example, consider a configuration having a "standard steering angle command value acquisition unit" and an "actual steering angle command value acquisition unit." The actual steering angle command value acquired by the actual steering angle command value acquisition unit corresponds to a command value (actual steering angle estimated lateral jerk) based on the actual steering angle (actual steering angle) of the steered wheels (e.g., front wheels 3, 3) of the vehicle. In this case, if only one steering angle command value exceeds the threshold, suspension control (roll control) can be performed by referring to that value. If both steering angle command values ​​exceed the threshold, suspension control (roll control) can be performed by referring to the largest steering angle command value. For example, if a steered wheel hits a fallen rock during autonomous driving (AD) and the actual steering angle changes significantly, suspension control (roll control) can be performed based on this change in the actual steering angle.

[0147] Also, for example, consider a configuration having an "input steering angle command value acquisition unit" and an "actual steering angle command value acquisition unit." In this case, if only one steering angle command value exceeds the threshold, suspension control (roll control) can be performed by referring to that value, and if both steering angle command values ​​exceed the threshold, suspension control (roll control) can be performed by referring to the larger steering angle command value. For example, if a steered wheel hits a fallen rock during normal driving and the actual steering angle changes significantly, suspension control (roll control) can be performed based on this change in the actual steering angle.

[0148] Furthermore, for example, consider a configuration having an "input steering angle command value acquisition unit," an "actual steering angle command value acquisition unit," and a "standard steering angle command value acquisition unit." In this case, if only one steering angle command value exceeds the threshold, suspension control (roll control) can be performed by referring to that value, and if two or more steering angle command values ​​exceed the threshold, suspension control (roll control) can be performed by referring to the largest steering angle command value among those values. For example, if a steered wheel hits a fallen rock during assisted driving (ADAS) and the actual steering angle changes significantly, suspension control (roll control) can be performed based on this change in the actual steering angle.

[0149] In each embodiment and each modified example, a vehicle 1 having a steer-by-wire steering device 10 has been described as an example. However, the present invention is not limited to this. For example, the steering device (steering device) does not have to be a steer-by-wire type. For example, the steering device (steering device) does not have to have a steering member. In this case, a configuration including a "standard steering angle command value acquisition unit" and an "actual steering angle command value acquisition unit" can be used. When only one steering angle command value is determined to have exceeded the threshold, the suspension can be controlled by referring to that value (standard steering angle command value or actual steering angle command value). When both command values ​​are determined to have exceeded the threshold, the largest steering angle command value of the values ​​(standard steering angle command value and actual steering angle command value) can be used to control the suspension.

[0150] In each embodiment and each modified example, the roll control unit, which is an anti-roll control unit, acquires a steering angle command value (lateral jerk), i.e., the roll control unit has a steering angle command value acquisition unit. However, this is not limiting. The steering angle command value acquisition unit may be included in a handling stability control unit other than the roll control unit, such as an anti-dive control unit (dive control unit) that calculates a control command for anti-dive control or an anti-dive control unit (dive control unit) that calculates a control command for anti-squat control. In other words, the steering angle command value acquisition unit may be included in a suspension control device (suspension control mechanism). The same applies to the speed acquisition unit, the determination unit, and the command value determination unit. In summary, a suspension control mechanism (suspension control device) that controls a vehicle suspension (suspension) may have a speed acquisition unit that acquires the vehicle speed, a steering angle command value acquisition unit that acquires a steering angle command value corresponding to the steering angle of the vehicle, a determination unit that determines whether the steering angle command value exceeds a threshold value, and a command value determination unit that controls the suspension by referring to the steering angle command value that the determination unit determines exceeds the threshold value.

[0151] In each embodiment and each modified example, the vehicle behavior detection means has been described using, as examples, a longitudinal acceleration sensor, a lateral acceleration sensor, a wheel speed sensor, a yaw rate sensor, a vehicle speed sensor, a vehicle height sensor, a sprung vertical acceleration sensor, a sprung vertical velocity sensor, an unsprung vertical acceleration sensor, an unsprung vertical velocity sensor, etc. However, without being limited thereto, sensors other than the exemplified sensors, such as a stroke sensor, a displacement sensor, a preview sensor (external environment recognition sensor), etc., may also be used as the vehicle behavior detection means. Examples of the preview sensor (external environment recognition sensor) that can be used include a camera (e.g., a digital camera) such as a stereo camera or a single camera, and / or a radar (e.g., a light-emitting element such as a semiconductor laser and a light-receiving element that receives the light) such as a laser radar, an infrared radar, or a millimeter-wave radar, a LiDAR, or a sonar.

[0152] In each embodiment and each modified example, the force generating mechanism (actuator) is described using an adjustable damping force shock absorber 6, 8. In this case, the adjustable damping force shock absorber 6, 8 is described using an adjustable damping force hydraulic shock absorber, i.e., a hydraulic semi-active damper. However, this is not limiting, and the adjustable damping force shock absorber may be another type of semi-active damper, such as an ER damper (electrorheological fluid damper). Furthermore, the force generating mechanism (actuator) may be a force generating mechanism capable of generating thrust, i.e., a fully active damper configured with a hydraulic actuator, an electric actuator, or a pneumatic actuator. In other words, the force generating mechanism (actuator) may be any of various force generating mechanisms (actuators), such as a variable damping force hydraulic damper, an electrorheological fluid damper, a pneumatic damper, an electromagnetic damper, a hydraulic actuator, an electric actuator, or a pneumatic actuator.

[0153] In each embodiment and each modified example, the damping force adjustable shock absorbers 6, 8 and the suspension control device 21 are mounted on an automobile as a vehicle. However, the present invention is not limited to this, and the damping force adjustable shock absorbers 6, 8 and the suspension control device 21 can be mounted on various vehicles other than automobiles, such as railway vehicles and work vehicles.

[0154] According to the embodiment described above, the determination unit determines whether multiple steering angle command values ​​(a reference steering angle command value based on a reference steering angle corresponding to a reference turning state of the vehicle, an input steering angle command value based on an input steering angle input to a steering member of the vehicle, and an actual steering angle command value based on an actual steering angle of a steered wheel of the vehicle) exceed their corresponding thresholds. The command value determination unit then controls the suspension by referring to a single steering angle command value if only one steering angle command value exceeds the threshold. If two or more command values ​​exceed the threshold, the command value determination unit controls the suspension by referring to the largest steering angle command value among the multiple steering angle command values. This allows the suspension to be controlled by referring to the steering angle command value that exceeds the threshold earliest among the multiple steering angle command values. In other words, the steering angle (reference steering angle, input steering angle, actual steering angle) that changes most quickly can be used for control. This allows the start timing of suspension control (e.g., anti-roll control) to be advanced and the control to be intervened at the required timing. This improves steering feel. Moreover, the steering feel can be improved by adjusting the software settings, which allows for improved performance while keeping costs down.

[0155] According to this embodiment, it is determined whether at least the input steering angle command value and the actual steering angle command value exceed their respective threshold values. In this case, the threshold value corresponding to the actual steering angle command value is greater than the threshold value corresponding to the input steering angle command value. Therefore, the suspension can be controlled by referring to the input steering angle command value until the actual steering angle command value exceeds the threshold value.

[0156] According to the embodiment, the input steering angle is a steering angle resulting from a steering operation of the steering wheel by the driver. Therefore, the suspension can be controlled using a steering angle command value based on the steering angle resulting from the steering operation of the steering wheel by the driver.

[0157] According to the embodiment, the steering device that steers the steered wheels is a steer-by-wire system, and the input steering angle is a steering angle resulting from a steering operation of the steering wheel by the driver. Therefore, the suspension device of the vehicle equipped with the steer-by-wire steering device can be controlled using a steering angle command value based on the steering angle resulting from the steering operation of the steering wheel by the driver.

[0158] According to an embodiment, when the product of the input steering angle input to the steering member of a vehicle in a steer-by-wire system and the vehicle speed is equal to or greater than a predetermined value, the supply of current or voltage to the suspension system is initiated. The predetermined value corresponds to a threshold value of a dead zone for suspension system control related to the input steering angle. In this case, the predetermined value can be set to a small value by regarding the input steering angle as corresponding to the driver's intention. Furthermore, since the predetermined value does not correspond to a threshold value of a dead zone related to the actual steering angle, which is the actual steering angle of the steered wheels of the vehicle, it can also be set to a small value from this perspective. This allows the start timing of suspension system control (e.g., anti-roll control) to be advanced and control to be intervened when necessary, thereby improving steering feel. Moreover, since the steering feel can be improved by configuring software, performance can be improved while suppressing increases in costs.

[0159] According to the embodiment, the input steering angle is expressed in units of arc degrees [rad], degrees [deg], or an angle converted into these, the vehicle speed is expressed in units of meters per second [m / s], or a speed converted into these, and the predetermined value is expressed in units of radian meters per second [rad m / s] or degree meters per second [deg m / s]. Therefore, the predetermined value can be set as a threshold value in units of radian meters per second [rad m / s] or degree meters per second [deg m / s].

[0160] According to this embodiment, when the product of the input steering angle and vehicle speed is greater than a predetermined value of 0 radian meters per second (rad·m / s) or 0 degrees meters per second (deg·m / s), the supply of current or voltage to the suspension system begins. This eliminates the steering-related suspension system control intervention threshold (deadband threshold), ensuring that any steering input will initiate suspension system control. In other words, with steer-by-wire, the steering wheel and road wheels are not mechanically coupled (there is no shaft, for example, an intermediate shaft), so road surface input is not transmitted to the steering wheel. Therefore, steering wheel input is considered an intentional operation by the driver, and suspension system control can be initiated without fail in response to the driver's intentional operation.

[0161] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0162] This application claims priority to Japanese Patent Application No. 2024-112436, filed July 12, 2024. The entire disclosure of Japanese Patent Application No. 2024-112436, filed July 12, 2024, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

[0163] DESCRIPTION OF SYMBOLS 1 Vehicle 5 Front wheel suspension (suspension device) 7 Rear wheel suspension (suspension device) 10 Steering device (turning device) 11 Steering wheel (steering member) 21 Suspension control device (suspension device control mechanism, speed acquisition unit, steering angle command value acquisition unit, reference steering angle command value acquisition unit, input steering angle command value acquisition unit, actual steering angle command value acquisition unit, judgment unit, command value determination unit)

Claims

1. A suspension control mechanism for controlling a suspension of a vehicle, the suspension control mechanism comprising: a speed acquisition unit for acquiring a vehicle speed of the vehicle; a steering angle command value acquisition unit for acquiring a steering angle command value corresponding to a steering angle of the vehicle, the steering angle command value acquisition unit acquiring a plurality of the steering angle command values ​​from a group including at least two of the following: a speed acquisition unit for acquiring a vehicle speed of the vehicle; a steering angle command value acquisition unit for acquiring a standard steering angle command value which is a command value based on the vehicle speed and a standard steering angle which is a steering angle corresponding to a standard turning state of the vehicle; an input steering angle command value acquisition unit for acquiring an input steering angle command value which is a command value based on the vehicle speed and an input steering angle which is a steering angle input to a steering member of the vehicle; and an actual steering angle command value acquisition unit for acquiring an actual steering angle command value which is a command value based on the vehicle speed and an actual steering angle which is an actual steering angle of a steered wheel of the vehicle; the steering angle command value acquisition unit acquiring a plurality of the steering angle command values ​​from a group including at least two of the following; and a determination unit for determining whether or not the plurality of acquired steering angle command values ​​exceed corresponding thresholds. a command value determination unit that, when the determination unit determines that only one steering angle command value has exceeded the threshold, controls the suspension by referring to that value, and when the determination unit determines that two or more command values ​​have exceeded the threshold, controls the suspension by referring to the largest steering angle command value among the values.

2. A suspension control mechanism according to claim 1, wherein the steering angle command value acquisition unit acquires at least the input steering angle command value and the actual steering angle command value, and among the threshold values ​​used by the judgment unit, the threshold value corresponding to the actual steering angle command value is greater than the threshold value corresponding to the input steering angle command value.

3. A suspension control mechanism according to claim 1, wherein the input steering angle is a steering angle resulting from a steering operation of the steering wheel by a driver.

4. A suspension control mechanism according to claim 1, wherein the steering device for steering the steered wheels is a steer-by-wire system, and the input steering angle is a steering angle resulting from a driver's steering operation on the steering wheel.

5. A suspension control method for controlling a suspension of a vehicle having a steer-by-wire system by supplying current or voltage, the suspension control method comprising: an input steering angle acquisition step for acquiring an input steering angle input to a steering member of the vehicle; a vehicle speed acquisition step for acquiring a vehicle speed of the vehicle; and a power supply step, executed after the input steering angle acquisition step and the vehicle speed acquisition step, for supplying the current or the voltage, which power supply step starts supplying the current or the voltage when the product of the input steering angle and the vehicle speed is equal to or greater than a predetermined value.

6. A suspension control method according to claim 5, wherein the input steering angle in the power supply step is in units of arc degrees [rad], degrees [deg], or an angle converted into these, the vehicle speed in the power supply step is in units of meters per second [m / s] or a speed converted into these, and the predetermined value of the multiplication result in the power supply step is in units of radian meters per second [rad m / s] or degrees meters per second [deg m / s].

7. A suspension control method according to claim 6, wherein the power supply step starts supplying the current or the voltage when the multiplication result is greater than the predetermined value of 0 radian meters per second [rad·m / s] or 0 degrees meters per second [deg·m / s].

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